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While looking for some info on my computer I came up with this little bit that Lee sent me......a while back.
This will answer just about any question you ever had about the scoping of an M14.
The book that he has (I have a few copies left) is much like this, maybe a little dry for some......and there are no pictures in the book?
Take it away Lee ( he does post here once and a while. )
M14 Scope Mount FAQ
by Lee Emerson (AKA Different)
04/04/05
The M14 type rifle was designed to accept a scope mount. The M14 can be securely scoped if the installation is properly done. The U. S. Army Picatinny Arsenal (Morris County, NJ) did a study on the difficulties of mounting a scope on the M14 rifle. The Naval Surface Warfare Center (Crane, IN) also worked on the issue.
The following companies have manufactured scope mounts for the M14 type rifle: Accuracy Speaks, Atlantic Research Marketing Systems, Inc., Armscorp USA, B-Square, Brookfield Precision Tool, Entreprise Arms, Global Defense Initiatives, Inc., GG&G, John Masen Company, Leatherwood Bros., McCann, S&K Manufacturing Co., Sadlak Industries, Smith Enterprise, Inc., Springfield Armory, Inc. and US Tactical Systems.
Brookfield Precision Tool, GG&G, Leatherwood Bros., and Smith Enterprise mounts have been used by the U. S. military on M14 type rifles. GG&G made M14 scope mounts for the U. S. Marine Corps only for its M14 DMR. These GG&G units were never available for commercial sale. Picatinny Arsenal conducted a study on the difficulties of mounting a scope on the M14 rifle. The U. S. Naval Surface Warfare Center (Crane, IN) also worked on the issue. Scope mount adapters were made for the AN/PVS-2 and 3 night scopes (NSN 5855-00-941-3036) by GPC Night Vision (CAGE Code 1YE66) and the AN/PVS-4 night scope by Brookfield Precision Tool.
Scope Rail Types
The two types of scope rails found on M14 scope mounts are the Weaver style and the Picatinny style. The Picatinny style is also known as the MIL-1913-STD rail or M1913 rail for short. U. S. military scopes use rings designed for the M1913 Picatinny style rail. Weaver scope mounts and rings are popular with civilian hunters. Weaver or Picatinny rings can be used on a M1913 Picatinny rail. A Weaver rail will accept Weaver rings.
Side Single Point Scope Mounts
The Basset Machine, Israeli Military Industries, S&K (# 1765) and Springfield Armory First Generation mounts attach to the receiver left hand side using the bolt hole only. They do not require removal of the stripper guide while the others do. The Bassett Machine and Springfield Armory mounts are made of aluminum except the Bassett Machine model has hardened steel keys. The Bassett Machine scope mount accepts Weaver style rings. Early Leatherwood mounts were made of aluminum and used a single point of contact to the receiver on the XM21 rifles.
Side Two Point Scope Mounts
The side two point design scope mount uses the receiver bolt hole and the stripper clip guide to secure the mount. The stripper clip guide must be removed before this type of scope mount can be installed. B-Square, Leapers, Inc., John Masen Company, McCann, Springfield Armory Third Generation, and latter military issue Leatherwood Brothers mounts are of the side two point design. The U. S. Army armorers installed side two point Leatherwood scope mounts on M21 rifles.
The Leapers, Inc. scope mount (Model # MNT914) is made from aircraft grade aluminum alloy and utilizes a Weaver rail. The iron sights can be used with the scope mount installed. The John Masen Company (# M14SM) aluminum alloy scope mount utilizes a Weaver rail. The McCann mount is made of steel and is supplied with two Weaver style ring bases. The rifle iron sights can be used up to about an elevation of 200 meters with a Springfield Armory, Inc. scope mount.
At higher elevation settings the mount will block the shooter's vision through the rear sight aperture. The Springfield Armory Third Generation mount uses a supplied substitute guide that replaces the stripper clip guide.
Side Three Point Scope Mounts
Mounts that have three points of contact with the receiver are the most reliable for keeping the scope zeroed. This scope mount style is very popular among M14 rifle enthusiasts. Several models are described below.
Brookfield Precision Tool - The Brookfield Precision Tool mount sits on the military XM25 and M25 rifles. Brookfield Precision Tool scope mounts were sold in the commercial market for a number of years. They now command a premium due to their collector value. The Brookfield Precision Tool mount allows the shooter to use the iron sights with or without the scope installed. It is a M1913 Picatinny style rail with a cam type mounting bolt designed to fit all four makes of USGI M14 receivers. Commercial M14 manufacturers do not and never have guaranteed their receivers meet the dimensional tolerances of USGI M14 receiver drawing 7790189. Therefore, slight dimensional differences exist between USGI and commercial manufacture M14 receivers. On the other hand, several but not all, manufacturers have designed their scope mounts to fit USGI M14 receivers. Bottom line, side three point scope mounts do not always fit hand-to-glove on all M14 type receivers.
Smith Enterprise, Inc. - Smith Enterprise scope mounts are made from AISI 4140 alloy steel and treated by nitrocarburizing. Surface hardness is 60 HRC. They have a matte black finish. As of 2003, the Smith Enterprise MIL-STD-1913 Picatinny rail tactical scope mount is stocked by the U. S. military supply system (NSN 5855-01-506-5750). It allows the shooter to use the iron sights with or without the scope installed. The scope mount with the marking NSN 5855--01-506-5750 is manufactured using the wire electro-discharge machining (EDM) method. EDM can be described as spark erosion of metals by local heating and melting. This metalworking method holds very tight tolerances and leaves burr free surfaces. Their earlier M14 scope mounts were made using conventional machining methods but are nonetheless just as trouble free and durable. The Smith Enterprise scope mount has a three degree upward slope on the under side of the rail portion. This allows ejected brass to clear the action while minimizing any contact with the mount because of varying receiver geometries among the manufacturers. This mount utilizes a cam type mounting bolt to compensate for the differing position of the bolt hole on various makes of rifles. For demonstration purposes only, Ron Smith installed a Smith Enterprise scope mount on a commercial manufacture M14 type receiver and torqued the receiver mounting bolt in increments to 140 in-lb. There was absolutely no damage to the bolt, mount or receiver. 65 in-lb of torque is sufficient for installing their scope mount. Installation instructions are included with every scope mount sold by Smith Enterprise. The mount installation instructions are also posted at their web site.
Armscorp USA - The Armscorp USA M14 scope mount is a very faithful copy of the Brookfield Precision Tool mount. It is machined from steel and heat treated to U. S. military specification. It has an adjustable cam bolt. The iron sights can be used with this mount installed without removing the scope.
Atlantic Research Marketing Systems, Inc. - The Atlantic Research Marketing Systems # 18 scope mount has been made in two versions. The early style was first introduced in 1989. It has two pads, one at each end, for mounting a scope ring. A few of the early style have an integral stripper clip guide in the rear pad. Introduced in 2003, the new style is a full length rail running from the stripper clip guide to the top of the barrel ring. Both models are M1913 Picatinny style rails. The # 18 scope mount sits low enough on the receiver to allow use of the iron sights if the scope is removed. It sits the lowest of any scope mount available. Due to differences in commercial receiver geometry the user may find that a little judicious removal of the front end under side corner may be necessary to get a # 18 mount to fit perfectly. The new style is made of case hardened AISI 8620 alloy steel.
Sadlak Industries - Since 2002, Sadlak Industries has made M14 scope mounts. It offers M1913 Picatinny style rail scope mounts manufactured from two different materials, titanium and steel. The titanium scope mounts are machined from hot rolled billet then heat treated to a hardness of 26 to 30 HRC. After heat treatment, the titanium mounts are finished with a matte black nitride coating for improved corrosion and abrasion resistance. This coating increases the surface hardness to approximately 80 HRC. The titanium scope mount is tougher and stronger than steel but 40 % lighter. The steel mounts are made from stress relieved AISI 4142 bar stock with a core hardness of 28 to 32 HRC. David Ferrante applies a military specification black manganese phosphate coating to the steel scope mounts. In the fall of 2004, Sadlak Industries delivered 108 steel M14 scope mounts to the New York Army National Guard and instructed the soldiers in installing these mounts.
A 7075 aluminum-magnesium-zinc alloy version of its M14 scope mount is in testing in November, 2004. This alloy is commonly used to fabricate aircraft frames. The aluminum alloy M14 scope mount is fully machined and hard coat anodized. The aluminum alloy M14 scope mount is expected to be available in early 2005.
The Sadlak Industries M14 scope mount is based on the Brookfield Precision Tool model. Sadlak incorporated some useful enhancements to its M14 scope mount in late 2004. Two setscrews securely hold the wider adjustable dovetail piece (clip guide key) to keep it from loosening. The rear end of the scope mount has cutouts to allow wrench access to the dovetail setscrews. The dovetail setscrews securely lock the dovetail piece (clip guide key) into the receiver. The scope mount hole for the adjustable dovetail piece (clip guide) screw has been machined with an oval slot and a larger counterbore to make it more compatible with non-USGI receivers. The front post screw size has been increased for a larger contact area with the receiver. The front screw has also been changed from a ½-28 fine thread to a 5/15-24 fine thread. The new size front screw reduces the number of hex head wrenches from three to two. The front screw and the dovetail key socket screw now both use the same size hex head wrench.
Upon customer request, the horizontal key of the scope mount can be machined 0.005 ” narrower to accommodate non-USGI dimension receivers and / or allow for elevation adjustment. The original nitride coating used on the titanium model was not always as consistent in color as desired. Sadlak Industries, LLC does not compromise on its quality control. So, those off-color mounts have been rejected even though all other inspections were satisfactory. Unfortunately, the rejection rate due to improper color only was unacceptedly high. Consequently, as of late 2004, Sadlak Industries is testing a second and more color consistent matte black nitride coating as well as a tungsten coating for the titanium M14 scope mounts. The tungsten coating is even more durable than the nitride coating and has a slight greenish-gray phosphate coloring reminiscent of older military weapons. Beginning in early 2005, a five degree relief angle will be machined into the bottom of its scope mounts to minimize interference from spent cases in rifles with worn ejector springs.
Entreprise Arms - This is a Weaver style rail scope mount. It is machined from AISI 4140 alloy steel. The Entreprise Arms web site lists it in two lengths, standard and extended. Their mount allows the shooter to use the iron sights with or without the scope installed. The M14 mounts have a military specification phosphate finish.
Global Defense Initiatives, Inc. - By no later than 2003, Global Defensive Initiatives, Inc. designed and produced a side three point mount that differed somewhat from the classic Brookfield Precision Tool design. Its G1 Optical Sight Mount did not allow the use of iron sights with the scope removed. However, the M1913 Picatinny rail extended rearward to a point just behind the rear sight aperture. The rear sight assembly stayed in place with the mount installed. The G1 Optical Sight Mount accommodated an optical sight requiring very short eye relief between the shooter and the ocular lens. The G1 Optical Scope Mount was made from 17-4 precipitation hardening stainless steel and finished with a black oxide coating.
Leatherwood Bros. - Leatherwood Bros has advertised their new three point rail mount in Shotgun News. All parts are made from steel. It allows the use of iron sights and will accept M1913 Picatinny style scope rings. They began shipping of their mount to customers in June, 2004.
Keng’s Firearms Specialty, T T International, and US Tactical Systems - These are moderately priced side three point scope mounts for the M14 type rifle. The Keng’s Firearms Specialty unit has a M1913 Picatinny rail. The T T International model TSA scope mount is made of hardened steel with a M1913 Picatinny rail. The US Tactical Systems model has a Weaver style rail and is made from AISI 4140 alloy steel. It is heat treated and has a black color nitride surface finish. The iron sights can be used with all of these mounts installed.
Amega Ranges, Inc. - In 2005, Amega Ranges produces a M1913 Picatinny rail barrel mount for the M14 type rifle. It is made of anodized black color 6005-T6 aluminum alloy. It will fit USGI and Springfield Armory, Inc. standard contour M14 type barrels. This rail mount runs from the front end of the barrel ring to the front band. The Amega Range barrel rail mount is attached to the M14 type rifle with screws with no other modification required for installation.
Scope Mounts Secured to the Rear Sight Pocket
In 1985, Smith Enterprise, Inc. designed and produced pre-production units of two models of long three point scope mounts. Both were 9.250 “ long. The rear end of both models mounted to the rear sight pocket. The front end of both models went past the barrel ring. One was TIG welded to the receiver while the other was bolted on at the rear sight pocket through the sight knob holes. The heads of the bolts for the rear sight pocket were the same diameter as the sight knobs. The project was not pursued since it was found that the market was not ready for this new style of scope mount in 1985.
The Springfield Armory, Inc. M25 and Accuracy Speaks, Inc. M1913 Picatinny rail scope mounts both mount to the rear sight pocket instead of the stripper clip guide dovetail and the barrel. The Accuracy Speaks mount will fit either the M1 Garand or M14 type rifle. This aluminum mount replaces the rear sight and firmly attaches to the barrel. Installation requires drilling and tapping the barrel and removal / modification of the hand guard.
In the past, Atlantic Research Marketing Systems, Inc. has made available its M-14/M-1A Rigid Rail Mount. This mount had a ring at the front end that fits around the barrel just forward of the receiver barrel ring. The rear end of the mount fits inside the rear sight pocket and was secured by a bolt through the sight knob holes. The M-14/M-1A Rigid Rail Mount had a M1913 Picatinny rail and was offered in two choices of material construction and three differing lengths. The material was a choice of either phosphate coated AISI 4140 alloy steel or an aluminum rail with steel barrel ring. The aluminum and steel model was hard coat anodized for the surface finish treatment. The mount was available in standard, extended front or extended rear lengths. The flash suppressor, gas system and operating rod guide must be removed to install this scope mount. Installation should be done by a gunsmith familiar with the M14 type rifle.
Rail System Mounts
Knight's Manufacturing Company (Titusville, FL) produces a M4 Carbine style rail system known as the M14 RAS offered in two models. The rear end of the top rail for both models ends at the receiver barrel ring. The deluxe model has a rear scope mount base that replaces the stripper clip guide. The standard model is the deluxe model without the rear scope mount base. This is a very solid mount and is easy to install. It allows the use of the rifle iron sights unless the rifle has a heavyweight contour barrel. The side ribbed accessory panels will interfere with a National Match oversized stock but not the USGI contour stocks. C. J. Weapons Accessories offers the Striker-14 M-14/M1A Tactical Rail System. It has three M1913 Picatinny rails with the rear end of the top rail attaching to the stripper clip guide. The iron sights can be used with a scope installed. It secures to the rifle at three points. It is CNC machined from a single piece of aluminum and has a black anodized finish.
Barrel Scope Mounts
Springfield Armory, Inc. offers a barrel mount for extended eye relief scopes. The M1A Scout Squad rifle is sold with the barrel mount installed. They also sell it separately. It is made of aluminum. It attaches to a standard contour barrel using six 7/32 " hex head screws that secure the upper half to the lower half of the mount. It will not fit on a medium weight, heavyweight or M1 Garand barrel. Springfield Armory, Inc. offers the Scout Squad Mount in a choice of black or brown. Rooster33 began producing and selling their own barrel scope mount in March, 2004. It is made of steel and sized for a lightweight (standard) contour M14 barrel. The Rooster33 scope mount attaches to the barrel by four hex head bolts.
Problems with Fitting Scope Mounts
Type of Material - Scope mounts are made using aluminum, steel and titanium. Aluminum is the least expensive and titanium the most expensive material of the three. Aluminum scope mounts are more prone to moving after repeated firing than steel or titanium mounts. This causes the scope to wander and the zero is lost. Aluminum is softer and it expands at a greater rate than the receiver AISI 8620 alloy steel.
Receiver Geometry - As far as the author knows, commercial M14 manufacturers do not and never have guaranteed their receivers meet the dimensional tolerances of USGI M14 receiver drawing 7790189. Therefore, slight dimensional differences exist between USGI and commercial made M14 receivers. On the other hand, several (not all) manufacturers have designed their scope mounts to fit USGI M14 receivers. Consequently, scope mounts do not always fit hand-to-glove on all M14 type receivers. Bill Ricca described the development of the BPT scope mount on www.m14forum.com:
I noticed the posting about certain times mounts must be slightly altered to fit the
receivers. Brookfield went thru the same problems and here is the scoop.
When the BPT mount was originally designed they were put on many M14's. The
production process was set up to fit all receivers of all makers. Then came the
commercial market and the nightmares began.
On the commercial market, at that time, receivers were all over the place as far as dimensions go. Armscorp had a few problems, SA had plenty of problems and Fed Ord[nance] was totally a waste of time. Believe or not the Chinese versions had no problems fitting at all.
The problem was steel receivers and steel mounts have absolutely no give whatsoever. Everybody was used to aluminum mounts which could be muscled into minor changes to fit.
SA also had the problem of the screw hole being undersized due to worn out reamers. The problem was random, but about 10% of all mounts sold ran into this problem. SA also had the problem of incorrect receiver rails which canted the steel mount sideways. Armscorp had fewer problems and as stated some Fed Ord[nance] were so far off the mount would not even go some rifles without major cutting of the dovetail and rails.
That was back then, but the main focus is as follows: If you purchase one of these steel mounts that have been sold to the military and it does not fit your rifle don't call the company and say "Something is wrong with your mount, it doesn't fit". The problem is in your receiver.
Mr. Ricca's sage advice apparently applies to USGI M14 receivers as well. Smith Enterprise, Inc. states that they have found as much as 0.010 " variance in a 3 " distance on USGI M14 receivers. From a November 15, 1998 discussion thread post on www.snipercountry.com
On the M21/25 and M1A/M14 scope mount question. We (Marine Corps Security Force, Pac) had good luck years back with the Brookfield mounts when we were developing a version of the DM rifle. The Navy was using the same mounts on their version and they were tack welding the bolts to hold the mounts on.
The only problem we had was with the receivers we were using not the scope mounts. It seems that many of the H&R receivers that we had were not manufactured to spec as far as the dimensions pertaining to the area where the scope mount mounts on the left side of the receiver. This gave us a ton of excessive windage when the scopes were mounted. We never had a problem with Winchester receivers. Be aware of this as you put the sucker together.
In the author's opinion, Smith Enterprise and post-’04 customer requested narrow key Sadlak Industries models are the most accommodating scope mount for commercial M14 receivers. Why? 1) adjustable cam which is more forgiving of misplaced receiver bolt holes 2) narrower horizontal key than the BPT mount to fit narrower commercial receiver grooves 3) relief angle on the under side of the rail to minimize stove piping of spent cases 4) no vertical key 5) scope mount can be adjusted during installation to minimize windage and elevation adjustments with the scope turrets for zero.
Side Three Point Scope Mount Fitting on Commercial M14 Receivers
There are five points of contact between the side three point scope mount and the receiver that may cause improper fit up with military design side three point scope mounts when installed on commercial M14 receivers. The surface contact between the left side of the scope mount and the left side of the receiver is of primary importance. The more contact between these two surfaces the less likely the mount is to shift from firing recoil. The scope mount should be tested first for fit without the stripper clip guide dovetail key supplied with the mount.
Receiver Bolt Hole - The USGI M14 receiver drawing specifies a distance of 1.500 " + or - 0.003 " for the distance between the bolt hole centerline and the front vertical edge of the barrel ring. If the bolt hole is drilled too far to the rear the scope mount rear end may contact the receiver stripper clip guide dovetail. This lifts the back of the mount so the mount horizontal key doesn't fully seat in the receiver horizontal groove. Consequently, the mount is moved left, right, or down at the front end. The rifle is then likely to shoot high or to one side. Additionally, some bolt holes are undersized due to worn out reamers or not drilled perfectly perpendicular to the receiver wall. A very few commercial receivers lack the scope mount recoil lug or bolt hole.
Receiver Horizontal Groove - The height, angle and width of the horizontal groove affect the fit of side three point scope mounts to M14 type receivers. Some commercial receivers have horizontal grooves too shallow and narrow to accommodate military specification mounts such as the Brookfield Precision Tool and Sadlak Industries models. The USGI drawing number 7790189 specification for the horizontal groove is 0.149 " to 0.153 ” wide at the top of the groove with a sixty degree angle from the bottom of the groove. The bottom of the horizontal groove should be 0.070 ” to 0.078 ” wide. Commercial receiver horizontal grooves can measure as narrow as 0.120 " at the top of the groove.
Receiver Barrel Ring - The top front left hand corner of the barrel ring may interfere with the new style Atlantic Research Marketing Systems # 18 scope mount. This is no fault of Atlantic Research Marketing Systems, Inc. as its mount was designed to fit on USGI M14 receivers.
Receiver Stripper Clip Guide Dovetail - The stripper clip guide dovetail may be machined such that the scope mount adjustable dovetail does will not slide in from the side of the bolt hole but may do so from the operating rod side. The height of the stripper clip guide dovetail may also be tall enough to push up on the rear end of the scope mount. The stripper clip guide dovetail has been found as much as 0.030 ” taller than USGI specification.
Barrel Hand Guard - The Atlantic Research Marketing Systems # 18 front rail pad setscrew may contact the hand guard. This can be remedied by replacing the setscrew with one that fits flush with the pad. Again, this is no fault of Atlantic Resarch Marketing Systems, Inc. Commercial receivers are not always machined to the USGI blueprint dimensions.
Smith Enterprise, Inc. states that they have found as much as 0.010 " variance in a 3 " distance on USGI M14 receivers. In the 1990s, the U. S. Marine Corps and U. S. Navy had great success with the Brookfield Precision Tool scope mounts. However, it was found by the U. S. Marine Corps that the location of Harrington & Richardson M14 receiver scope mount bolt holes caused excessive windage adjustment to zero the scopes. The U. S. Marine Corps had no such problems with the Winchester M14 rifle receivers.
Tips for Installing Your M14 Scope Mount
Disclaimer - The following are suggestions intended to help those who install scope mounts on M14 type rifles. If something does not fit easily, stop immediately and seek assistance from a professional gunsmith, preferably one experienced with M14 type rifles. Always make sure the rifle is unloaded prior to commencing any work. Wear eye protection. The author cannot be held liable for any damage or misfortune as a result of installing a scope mount on a rifle.
There are some common pitfalls that can be avoided making successful installation a reality. The task at hand is to securely attach the mount to the rifle so that it is parallel to the barrel line of sight. First and always, read the manufacturer's instructions carefully. If you don't have the instructions, obtain them from the manufacturer. Use the proper tools. This includes using a torque wrench calibrated in inch-pounds of force not foot-pounds of force. Additional tools may include 1/4 " drive socket for the receiver bolt, small flat tip jeweler's screwdriver, large flat tip screwdriver, 3 / 32 " pin punch to drive out the stripper clip guide pin, brass drift and small hammer to remove the stripper clip guide and appropriate size hex head wrenches for tightening the mount in place. Manufacturers such as Atlantic Research Marketing Systems, Inc., Sadlak Industries, LLC, and Smith Enterprise, Inc. supply the necessary hex head wrenches. Hex head wrench sizes will vary from 3 / 16 " to 5 / 32 " depending on the make of the scope mount.
The stripper clip guide should be gently tapped out from right to left with the muzzle pointed away from the worker. DO NOT force the stripper clip guide out. It should be easy to tap out. Degrease the receiver bolt hole, the mounting bolt and all screw threads prior to installation. Be careful not to cross-thread any screw or bolt. DO NOT exceed the manufacturer torque specifications. DO use blue color Loctite 242 threadlocker as this will permanently attach the mount to the receiver. DO NOT use any other color Loctite threadlocker. DO NOT weld a scope mount to the receiver.
If need be, totally remove the screw from the mount stripper clip adjustable dove tail / guide key. Fit up the scope mount then gently slide the adjustable dove tail / guide key in from the right side, line up the dove tail and mount holes, then put in the screw.
Atlantic Research Marketing Systems, Inc. # 18 Scope Mounts - In addition to the instructions supplied, the following tips will assist the installer. Prior to fitting up the mount, make sure the threaded circular spacer in the rear rail pad is turned into the pad so that it is not touching the receiver stripper clip guide dove tail on fit up. If the receiver mounting bolt is overtorqued, a replacement can be purchased from Atlantic Research Marketing Systems, Inc. If the front rail pad set screw interferes with the barrel hand guard replace it. A proper thread size flush fitting set screw is available from Dan's Shooting Supply or a hardware store. This is a 6-40 fine thread 3/16 " hex head screw. Alternately, one can use the flash suppressor nut set screw after removing the bare narrow tip. This will help center the mount with the barrel in such instances.
Some commercial M14 receivers may have extra material at the top left hand front corner of the barrel ring. This may interfere with the fit up of the Atlantic Research Marketing Systems # 18 scope mount. Another tip is to use some modeling clay to indicate spots under the mount where the receiver is interfering. Apply a thin layer of modeling clay on the receiver where the mount fits against it. Put talcum powder on the under side of the mount to prevent the clay from adhering to the mount. Fit the mount up moderately snug. Then carefully remove the mount from the receiver. Observe where the mount is contacting the receiver. Using a Dremel tool with a sanding drum, carefully and slowly remove the interfering metal from the scope mount. Go slow. Repeat this procedure until all screws can be properly torqued.
If the the receiver barrel ring is not interfering with the fit of the mount, check the fit of the vertical key (the key above the bolt hole) to the receiver vertical groove. It may be helpful to carefully and slowly reduce the width of the vertical key to compensate for too narrow a vertical receiver groove. Use a diamond cutter or carbide cutter in the Dremel tool for the vertical key. Use the highest speed with a VERY light touch. Brace your hands to steady the tool. If need be, use a magnifying glass to observe the cutting of the Dremel tool. Take your time to avoid removing too much metal from the mount. Touch up ground metal with cold blue.
Smith Enterprise M14 Scope Mount - The company web site ww.smithenterprise.com has installation instructions for their scope mount. Included in these instructions are directions for adjustment of the scope mount to minimize elevation and windage adjustments with the scope turrets. Replacement bolts and set screws are available from Smith Enterprise.
This will answer just about any question you ever had about the scoping of an M14.
The book that he has (I have a few copies left) is much like this, maybe a little dry for some......and there are no pictures in the book?
Take it away Lee ( he does post here once and a while.
)M14 Scope Mount FAQ
by Lee Emerson (AKA Different)
04/04/05
The M14 type rifle was designed to accept a scope mount. The M14 can be securely scoped if the installation is properly done. The U. S. Army Picatinny Arsenal (Morris County, NJ) did a study on the difficulties of mounting a scope on the M14 rifle. The Naval Surface Warfare Center (Crane, IN) also worked on the issue.
The following companies have manufactured scope mounts for the M14 type rifle: Accuracy Speaks, Atlantic Research Marketing Systems, Inc., Armscorp USA, B-Square, Brookfield Precision Tool, Entreprise Arms, Global Defense Initiatives, Inc., GG&G, John Masen Company, Leatherwood Bros., McCann, S&K Manufacturing Co., Sadlak Industries, Smith Enterprise, Inc., Springfield Armory, Inc. and US Tactical Systems.
Brookfield Precision Tool, GG&G, Leatherwood Bros., and Smith Enterprise mounts have been used by the U. S. military on M14 type rifles. GG&G made M14 scope mounts for the U. S. Marine Corps only for its M14 DMR. These GG&G units were never available for commercial sale. Picatinny Arsenal conducted a study on the difficulties of mounting a scope on the M14 rifle. The U. S. Naval Surface Warfare Center (Crane, IN) also worked on the issue. Scope mount adapters were made for the AN/PVS-2 and 3 night scopes (NSN 5855-00-941-3036) by GPC Night Vision (CAGE Code 1YE66) and the AN/PVS-4 night scope by Brookfield Precision Tool.
Scope Rail Types
The two types of scope rails found on M14 scope mounts are the Weaver style and the Picatinny style. The Picatinny style is also known as the MIL-1913-STD rail or M1913 rail for short. U. S. military scopes use rings designed for the M1913 Picatinny style rail. Weaver scope mounts and rings are popular with civilian hunters. Weaver or Picatinny rings can be used on a M1913 Picatinny rail. A Weaver rail will accept Weaver rings.
Side Single Point Scope Mounts
The Basset Machine, Israeli Military Industries, S&K (# 1765) and Springfield Armory First Generation mounts attach to the receiver left hand side using the bolt hole only. They do not require removal of the stripper guide while the others do. The Bassett Machine and Springfield Armory mounts are made of aluminum except the Bassett Machine model has hardened steel keys. The Bassett Machine scope mount accepts Weaver style rings. Early Leatherwood mounts were made of aluminum and used a single point of contact to the receiver on the XM21 rifles.
Side Two Point Scope Mounts
The side two point design scope mount uses the receiver bolt hole and the stripper clip guide to secure the mount. The stripper clip guide must be removed before this type of scope mount can be installed. B-Square, Leapers, Inc., John Masen Company, McCann, Springfield Armory Third Generation, and latter military issue Leatherwood Brothers mounts are of the side two point design. The U. S. Army armorers installed side two point Leatherwood scope mounts on M21 rifles.
The Leapers, Inc. scope mount (Model # MNT914) is made from aircraft grade aluminum alloy and utilizes a Weaver rail. The iron sights can be used with the scope mount installed. The John Masen Company (# M14SM) aluminum alloy scope mount utilizes a Weaver rail. The McCann mount is made of steel and is supplied with two Weaver style ring bases. The rifle iron sights can be used up to about an elevation of 200 meters with a Springfield Armory, Inc. scope mount.
At higher elevation settings the mount will block the shooter's vision through the rear sight aperture. The Springfield Armory Third Generation mount uses a supplied substitute guide that replaces the stripper clip guide.
Side Three Point Scope Mounts
Mounts that have three points of contact with the receiver are the most reliable for keeping the scope zeroed. This scope mount style is very popular among M14 rifle enthusiasts. Several models are described below.
Brookfield Precision Tool - The Brookfield Precision Tool mount sits on the military XM25 and M25 rifles. Brookfield Precision Tool scope mounts were sold in the commercial market for a number of years. They now command a premium due to their collector value. The Brookfield Precision Tool mount allows the shooter to use the iron sights with or without the scope installed. It is a M1913 Picatinny style rail with a cam type mounting bolt designed to fit all four makes of USGI M14 receivers. Commercial M14 manufacturers do not and never have guaranteed their receivers meet the dimensional tolerances of USGI M14 receiver drawing 7790189. Therefore, slight dimensional differences exist between USGI and commercial manufacture M14 receivers. On the other hand, several but not all, manufacturers have designed their scope mounts to fit USGI M14 receivers. Bottom line, side three point scope mounts do not always fit hand-to-glove on all M14 type receivers.
Smith Enterprise, Inc. - Smith Enterprise scope mounts are made from AISI 4140 alloy steel and treated by nitrocarburizing. Surface hardness is 60 HRC. They have a matte black finish. As of 2003, the Smith Enterprise MIL-STD-1913 Picatinny rail tactical scope mount is stocked by the U. S. military supply system (NSN 5855-01-506-5750). It allows the shooter to use the iron sights with or without the scope installed. The scope mount with the marking NSN 5855--01-506-5750 is manufactured using the wire electro-discharge machining (EDM) method. EDM can be described as spark erosion of metals by local heating and melting. This metalworking method holds very tight tolerances and leaves burr free surfaces. Their earlier M14 scope mounts were made using conventional machining methods but are nonetheless just as trouble free and durable. The Smith Enterprise scope mount has a three degree upward slope on the under side of the rail portion. This allows ejected brass to clear the action while minimizing any contact with the mount because of varying receiver geometries among the manufacturers. This mount utilizes a cam type mounting bolt to compensate for the differing position of the bolt hole on various makes of rifles. For demonstration purposes only, Ron Smith installed a Smith Enterprise scope mount on a commercial manufacture M14 type receiver and torqued the receiver mounting bolt in increments to 140 in-lb. There was absolutely no damage to the bolt, mount or receiver. 65 in-lb of torque is sufficient for installing their scope mount. Installation instructions are included with every scope mount sold by Smith Enterprise. The mount installation instructions are also posted at their web site.
Armscorp USA - The Armscorp USA M14 scope mount is a very faithful copy of the Brookfield Precision Tool mount. It is machined from steel and heat treated to U. S. military specification. It has an adjustable cam bolt. The iron sights can be used with this mount installed without removing the scope.
Atlantic Research Marketing Systems, Inc. - The Atlantic Research Marketing Systems # 18 scope mount has been made in two versions. The early style was first introduced in 1989. It has two pads, one at each end, for mounting a scope ring. A few of the early style have an integral stripper clip guide in the rear pad. Introduced in 2003, the new style is a full length rail running from the stripper clip guide to the top of the barrel ring. Both models are M1913 Picatinny style rails. The # 18 scope mount sits low enough on the receiver to allow use of the iron sights if the scope is removed. It sits the lowest of any scope mount available. Due to differences in commercial receiver geometry the user may find that a little judicious removal of the front end under side corner may be necessary to get a # 18 mount to fit perfectly. The new style is made of case hardened AISI 8620 alloy steel.
Sadlak Industries - Since 2002, Sadlak Industries has made M14 scope mounts. It offers M1913 Picatinny style rail scope mounts manufactured from two different materials, titanium and steel. The titanium scope mounts are machined from hot rolled billet then heat treated to a hardness of 26 to 30 HRC. After heat treatment, the titanium mounts are finished with a matte black nitride coating for improved corrosion and abrasion resistance. This coating increases the surface hardness to approximately 80 HRC. The titanium scope mount is tougher and stronger than steel but 40 % lighter. The steel mounts are made from stress relieved AISI 4142 bar stock with a core hardness of 28 to 32 HRC. David Ferrante applies a military specification black manganese phosphate coating to the steel scope mounts. In the fall of 2004, Sadlak Industries delivered 108 steel M14 scope mounts to the New York Army National Guard and instructed the soldiers in installing these mounts.
A 7075 aluminum-magnesium-zinc alloy version of its M14 scope mount is in testing in November, 2004. This alloy is commonly used to fabricate aircraft frames. The aluminum alloy M14 scope mount is fully machined and hard coat anodized. The aluminum alloy M14 scope mount is expected to be available in early 2005.
The Sadlak Industries M14 scope mount is based on the Brookfield Precision Tool model. Sadlak incorporated some useful enhancements to its M14 scope mount in late 2004. Two setscrews securely hold the wider adjustable dovetail piece (clip guide key) to keep it from loosening. The rear end of the scope mount has cutouts to allow wrench access to the dovetail setscrews. The dovetail setscrews securely lock the dovetail piece (clip guide key) into the receiver. The scope mount hole for the adjustable dovetail piece (clip guide) screw has been machined with an oval slot and a larger counterbore to make it more compatible with non-USGI receivers. The front post screw size has been increased for a larger contact area with the receiver. The front screw has also been changed from a ½-28 fine thread to a 5/15-24 fine thread. The new size front screw reduces the number of hex head wrenches from three to two. The front screw and the dovetail key socket screw now both use the same size hex head wrench.
Upon customer request, the horizontal key of the scope mount can be machined 0.005 ” narrower to accommodate non-USGI dimension receivers and / or allow for elevation adjustment. The original nitride coating used on the titanium model was not always as consistent in color as desired. Sadlak Industries, LLC does not compromise on its quality control. So, those off-color mounts have been rejected even though all other inspections were satisfactory. Unfortunately, the rejection rate due to improper color only was unacceptedly high. Consequently, as of late 2004, Sadlak Industries is testing a second and more color consistent matte black nitride coating as well as a tungsten coating for the titanium M14 scope mounts. The tungsten coating is even more durable than the nitride coating and has a slight greenish-gray phosphate coloring reminiscent of older military weapons. Beginning in early 2005, a five degree relief angle will be machined into the bottom of its scope mounts to minimize interference from spent cases in rifles with worn ejector springs.
Entreprise Arms - This is a Weaver style rail scope mount. It is machined from AISI 4140 alloy steel. The Entreprise Arms web site lists it in two lengths, standard and extended. Their mount allows the shooter to use the iron sights with or without the scope installed. The M14 mounts have a military specification phosphate finish.
Global Defense Initiatives, Inc. - By no later than 2003, Global Defensive Initiatives, Inc. designed and produced a side three point mount that differed somewhat from the classic Brookfield Precision Tool design. Its G1 Optical Sight Mount did not allow the use of iron sights with the scope removed. However, the M1913 Picatinny rail extended rearward to a point just behind the rear sight aperture. The rear sight assembly stayed in place with the mount installed. The G1 Optical Sight Mount accommodated an optical sight requiring very short eye relief between the shooter and the ocular lens. The G1 Optical Scope Mount was made from 17-4 precipitation hardening stainless steel and finished with a black oxide coating.
Leatherwood Bros. - Leatherwood Bros has advertised their new three point rail mount in Shotgun News. All parts are made from steel. It allows the use of iron sights and will accept M1913 Picatinny style scope rings. They began shipping of their mount to customers in June, 2004.
Keng’s Firearms Specialty, T T International, and US Tactical Systems - These are moderately priced side three point scope mounts for the M14 type rifle. The Keng’s Firearms Specialty unit has a M1913 Picatinny rail. The T T International model TSA scope mount is made of hardened steel with a M1913 Picatinny rail. The US Tactical Systems model has a Weaver style rail and is made from AISI 4140 alloy steel. It is heat treated and has a black color nitride surface finish. The iron sights can be used with all of these mounts installed.
Amega Ranges, Inc. - In 2005, Amega Ranges produces a M1913 Picatinny rail barrel mount for the M14 type rifle. It is made of anodized black color 6005-T6 aluminum alloy. It will fit USGI and Springfield Armory, Inc. standard contour M14 type barrels. This rail mount runs from the front end of the barrel ring to the front band. The Amega Range barrel rail mount is attached to the M14 type rifle with screws with no other modification required for installation.
Scope Mounts Secured to the Rear Sight Pocket
In 1985, Smith Enterprise, Inc. designed and produced pre-production units of two models of long three point scope mounts. Both were 9.250 “ long. The rear end of both models mounted to the rear sight pocket. The front end of both models went past the barrel ring. One was TIG welded to the receiver while the other was bolted on at the rear sight pocket through the sight knob holes. The heads of the bolts for the rear sight pocket were the same diameter as the sight knobs. The project was not pursued since it was found that the market was not ready for this new style of scope mount in 1985.
The Springfield Armory, Inc. M25 and Accuracy Speaks, Inc. M1913 Picatinny rail scope mounts both mount to the rear sight pocket instead of the stripper clip guide dovetail and the barrel. The Accuracy Speaks mount will fit either the M1 Garand or M14 type rifle. This aluminum mount replaces the rear sight and firmly attaches to the barrel. Installation requires drilling and tapping the barrel and removal / modification of the hand guard.
In the past, Atlantic Research Marketing Systems, Inc. has made available its M-14/M-1A Rigid Rail Mount. This mount had a ring at the front end that fits around the barrel just forward of the receiver barrel ring. The rear end of the mount fits inside the rear sight pocket and was secured by a bolt through the sight knob holes. The M-14/M-1A Rigid Rail Mount had a M1913 Picatinny rail and was offered in two choices of material construction and three differing lengths. The material was a choice of either phosphate coated AISI 4140 alloy steel or an aluminum rail with steel barrel ring. The aluminum and steel model was hard coat anodized for the surface finish treatment. The mount was available in standard, extended front or extended rear lengths. The flash suppressor, gas system and operating rod guide must be removed to install this scope mount. Installation should be done by a gunsmith familiar with the M14 type rifle.
Rail System Mounts
Knight's Manufacturing Company (Titusville, FL) produces a M4 Carbine style rail system known as the M14 RAS offered in two models. The rear end of the top rail for both models ends at the receiver barrel ring. The deluxe model has a rear scope mount base that replaces the stripper clip guide. The standard model is the deluxe model without the rear scope mount base. This is a very solid mount and is easy to install. It allows the use of the rifle iron sights unless the rifle has a heavyweight contour barrel. The side ribbed accessory panels will interfere with a National Match oversized stock but not the USGI contour stocks. C. J. Weapons Accessories offers the Striker-14 M-14/M1A Tactical Rail System. It has three M1913 Picatinny rails with the rear end of the top rail attaching to the stripper clip guide. The iron sights can be used with a scope installed. It secures to the rifle at three points. It is CNC machined from a single piece of aluminum and has a black anodized finish.
Barrel Scope Mounts
Springfield Armory, Inc. offers a barrel mount for extended eye relief scopes. The M1A Scout Squad rifle is sold with the barrel mount installed. They also sell it separately. It is made of aluminum. It attaches to a standard contour barrel using six 7/32 " hex head screws that secure the upper half to the lower half of the mount. It will not fit on a medium weight, heavyweight or M1 Garand barrel. Springfield Armory, Inc. offers the Scout Squad Mount in a choice of black or brown. Rooster33 began producing and selling their own barrel scope mount in March, 2004. It is made of steel and sized for a lightweight (standard) contour M14 barrel. The Rooster33 scope mount attaches to the barrel by four hex head bolts.
Problems with Fitting Scope Mounts
Type of Material - Scope mounts are made using aluminum, steel and titanium. Aluminum is the least expensive and titanium the most expensive material of the three. Aluminum scope mounts are more prone to moving after repeated firing than steel or titanium mounts. This causes the scope to wander and the zero is lost. Aluminum is softer and it expands at a greater rate than the receiver AISI 8620 alloy steel.
Receiver Geometry - As far as the author knows, commercial M14 manufacturers do not and never have guaranteed their receivers meet the dimensional tolerances of USGI M14 receiver drawing 7790189. Therefore, slight dimensional differences exist between USGI and commercial made M14 receivers. On the other hand, several (not all) manufacturers have designed their scope mounts to fit USGI M14 receivers. Consequently, scope mounts do not always fit hand-to-glove on all M14 type receivers. Bill Ricca described the development of the BPT scope mount on www.m14forum.com:
I noticed the posting about certain times mounts must be slightly altered to fit the
receivers. Brookfield went thru the same problems and here is the scoop.
When the BPT mount was originally designed they were put on many M14's. The
production process was set up to fit all receivers of all makers. Then came the
commercial market and the nightmares began.
On the commercial market, at that time, receivers were all over the place as far as dimensions go. Armscorp had a few problems, SA had plenty of problems and Fed Ord[nance] was totally a waste of time. Believe or not the Chinese versions had no problems fitting at all.
The problem was steel receivers and steel mounts have absolutely no give whatsoever. Everybody was used to aluminum mounts which could be muscled into minor changes to fit.
SA also had the problem of the screw hole being undersized due to worn out reamers. The problem was random, but about 10% of all mounts sold ran into this problem. SA also had the problem of incorrect receiver rails which canted the steel mount sideways. Armscorp had fewer problems and as stated some Fed Ord[nance] were so far off the mount would not even go some rifles without major cutting of the dovetail and rails.
That was back then, but the main focus is as follows: If you purchase one of these steel mounts that have been sold to the military and it does not fit your rifle don't call the company and say "Something is wrong with your mount, it doesn't fit". The problem is in your receiver.
Mr. Ricca's sage advice apparently applies to USGI M14 receivers as well. Smith Enterprise, Inc. states that they have found as much as 0.010 " variance in a 3 " distance on USGI M14 receivers. From a November 15, 1998 discussion thread post on www.snipercountry.com
On the M21/25 and M1A/M14 scope mount question. We (Marine Corps Security Force, Pac) had good luck years back with the Brookfield mounts when we were developing a version of the DM rifle. The Navy was using the same mounts on their version and they were tack welding the bolts to hold the mounts on.
The only problem we had was with the receivers we were using not the scope mounts. It seems that many of the H&R receivers that we had were not manufactured to spec as far as the dimensions pertaining to the area where the scope mount mounts on the left side of the receiver. This gave us a ton of excessive windage when the scopes were mounted. We never had a problem with Winchester receivers. Be aware of this as you put the sucker together.
In the author's opinion, Smith Enterprise and post-’04 customer requested narrow key Sadlak Industries models are the most accommodating scope mount for commercial M14 receivers. Why? 1) adjustable cam which is more forgiving of misplaced receiver bolt holes 2) narrower horizontal key than the BPT mount to fit narrower commercial receiver grooves 3) relief angle on the under side of the rail to minimize stove piping of spent cases 4) no vertical key 5) scope mount can be adjusted during installation to minimize windage and elevation adjustments with the scope turrets for zero.
Side Three Point Scope Mount Fitting on Commercial M14 Receivers
There are five points of contact between the side three point scope mount and the receiver that may cause improper fit up with military design side three point scope mounts when installed on commercial M14 receivers. The surface contact between the left side of the scope mount and the left side of the receiver is of primary importance. The more contact between these two surfaces the less likely the mount is to shift from firing recoil. The scope mount should be tested first for fit without the stripper clip guide dovetail key supplied with the mount.
Receiver Bolt Hole - The USGI M14 receiver drawing specifies a distance of 1.500 " + or - 0.003 " for the distance between the bolt hole centerline and the front vertical edge of the barrel ring. If the bolt hole is drilled too far to the rear the scope mount rear end may contact the receiver stripper clip guide dovetail. This lifts the back of the mount so the mount horizontal key doesn't fully seat in the receiver horizontal groove. Consequently, the mount is moved left, right, or down at the front end. The rifle is then likely to shoot high or to one side. Additionally, some bolt holes are undersized due to worn out reamers or not drilled perfectly perpendicular to the receiver wall. A very few commercial receivers lack the scope mount recoil lug or bolt hole.
Receiver Horizontal Groove - The height, angle and width of the horizontal groove affect the fit of side three point scope mounts to M14 type receivers. Some commercial receivers have horizontal grooves too shallow and narrow to accommodate military specification mounts such as the Brookfield Precision Tool and Sadlak Industries models. The USGI drawing number 7790189 specification for the horizontal groove is 0.149 " to 0.153 ” wide at the top of the groove with a sixty degree angle from the bottom of the groove. The bottom of the horizontal groove should be 0.070 ” to 0.078 ” wide. Commercial receiver horizontal grooves can measure as narrow as 0.120 " at the top of the groove.
Receiver Barrel Ring - The top front left hand corner of the barrel ring may interfere with the new style Atlantic Research Marketing Systems # 18 scope mount. This is no fault of Atlantic Research Marketing Systems, Inc. as its mount was designed to fit on USGI M14 receivers.
Receiver Stripper Clip Guide Dovetail - The stripper clip guide dovetail may be machined such that the scope mount adjustable dovetail does will not slide in from the side of the bolt hole but may do so from the operating rod side. The height of the stripper clip guide dovetail may also be tall enough to push up on the rear end of the scope mount. The stripper clip guide dovetail has been found as much as 0.030 ” taller than USGI specification.
Barrel Hand Guard - The Atlantic Research Marketing Systems # 18 front rail pad setscrew may contact the hand guard. This can be remedied by replacing the setscrew with one that fits flush with the pad. Again, this is no fault of Atlantic Resarch Marketing Systems, Inc. Commercial receivers are not always machined to the USGI blueprint dimensions.
Smith Enterprise, Inc. states that they have found as much as 0.010 " variance in a 3 " distance on USGI M14 receivers. In the 1990s, the U. S. Marine Corps and U. S. Navy had great success with the Brookfield Precision Tool scope mounts. However, it was found by the U. S. Marine Corps that the location of Harrington & Richardson M14 receiver scope mount bolt holes caused excessive windage adjustment to zero the scopes. The U. S. Marine Corps had no such problems with the Winchester M14 rifle receivers.
Tips for Installing Your M14 Scope Mount
Disclaimer - The following are suggestions intended to help those who install scope mounts on M14 type rifles. If something does not fit easily, stop immediately and seek assistance from a professional gunsmith, preferably one experienced with M14 type rifles. Always make sure the rifle is unloaded prior to commencing any work. Wear eye protection. The author cannot be held liable for any damage or misfortune as a result of installing a scope mount on a rifle.
There are some common pitfalls that can be avoided making successful installation a reality. The task at hand is to securely attach the mount to the rifle so that it is parallel to the barrel line of sight. First and always, read the manufacturer's instructions carefully. If you don't have the instructions, obtain them from the manufacturer. Use the proper tools. This includes using a torque wrench calibrated in inch-pounds of force not foot-pounds of force. Additional tools may include 1/4 " drive socket for the receiver bolt, small flat tip jeweler's screwdriver, large flat tip screwdriver, 3 / 32 " pin punch to drive out the stripper clip guide pin, brass drift and small hammer to remove the stripper clip guide and appropriate size hex head wrenches for tightening the mount in place. Manufacturers such as Atlantic Research Marketing Systems, Inc., Sadlak Industries, LLC, and Smith Enterprise, Inc. supply the necessary hex head wrenches. Hex head wrench sizes will vary from 3 / 16 " to 5 / 32 " depending on the make of the scope mount.
The stripper clip guide should be gently tapped out from right to left with the muzzle pointed away from the worker. DO NOT force the stripper clip guide out. It should be easy to tap out. Degrease the receiver bolt hole, the mounting bolt and all screw threads prior to installation. Be careful not to cross-thread any screw or bolt. DO NOT exceed the manufacturer torque specifications. DO use blue color Loctite 242 threadlocker as this will permanently attach the mount to the receiver. DO NOT use any other color Loctite threadlocker. DO NOT weld a scope mount to the receiver.
If need be, totally remove the screw from the mount stripper clip adjustable dove tail / guide key. Fit up the scope mount then gently slide the adjustable dove tail / guide key in from the right side, line up the dove tail and mount holes, then put in the screw.
Atlantic Research Marketing Systems, Inc. # 18 Scope Mounts - In addition to the instructions supplied, the following tips will assist the installer. Prior to fitting up the mount, make sure the threaded circular spacer in the rear rail pad is turned into the pad so that it is not touching the receiver stripper clip guide dove tail on fit up. If the receiver mounting bolt is overtorqued, a replacement can be purchased from Atlantic Research Marketing Systems, Inc. If the front rail pad set screw interferes with the barrel hand guard replace it. A proper thread size flush fitting set screw is available from Dan's Shooting Supply or a hardware store. This is a 6-40 fine thread 3/16 " hex head screw. Alternately, one can use the flash suppressor nut set screw after removing the bare narrow tip. This will help center the mount with the barrel in such instances.
Some commercial M14 receivers may have extra material at the top left hand front corner of the barrel ring. This may interfere with the fit up of the Atlantic Research Marketing Systems # 18 scope mount. Another tip is to use some modeling clay to indicate spots under the mount where the receiver is interfering. Apply a thin layer of modeling clay on the receiver where the mount fits against it. Put talcum powder on the under side of the mount to prevent the clay from adhering to the mount. Fit the mount up moderately snug. Then carefully remove the mount from the receiver. Observe where the mount is contacting the receiver. Using a Dremel tool with a sanding drum, carefully and slowly remove the interfering metal from the scope mount. Go slow. Repeat this procedure until all screws can be properly torqued.
If the the receiver barrel ring is not interfering with the fit of the mount, check the fit of the vertical key (the key above the bolt hole) to the receiver vertical groove. It may be helpful to carefully and slowly reduce the width of the vertical key to compensate for too narrow a vertical receiver groove. Use a diamond cutter or carbide cutter in the Dremel tool for the vertical key. Use the highest speed with a VERY light touch. Brace your hands to steady the tool. If need be, use a magnifying glass to observe the cutting of the Dremel tool. Take your time to avoid removing too much metal from the mount. Touch up ground metal with cold blue.
Smith Enterprise M14 Scope Mount - The company web site ww.smithenterprise.com has installation instructions for their scope mount. Included in these instructions are directions for adjustment of the scope mount to minimize elevation and windage adjustments with the scope turrets. Replacement bolts and set screws are available from Smith Enterprise.
