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Design and Fabrication of my LTR muzzleloader
I thought I would post my black powder winter build project. This is my tenth rifle build, and the first one that I documented from start to finish. It’s also my second non-traditional build – an all original design built from scratch.
This is a design that resulted from a couple of factors; first and most importantly, I can no longer support the forward weight of a traditionally designed muzzleloader due to surgery on my left hand/wrist last year. Secondly, I wanted to cross pollinate a rifle design from my experience as a tech in the military as well as my black powder build experiences with muskets, rifles and cannon.
The overall design itself may seem familiar and that term bull-pup will pop into any firearms enthusiast immediately. By its very definition, it's a term that I have decided not to use when referring to this flintlock design. Instead, I will use the terminology lock-to-rear or LTR flintlock. As this is the first version of this design, with three design revisions - it is designated as the Mark 1, Revision C, or LTR Mk 1c.
Design, planning and component prototyping began in early 2010, and took a total of eight months off and on. Most of the fabrication work took 10 weeks for several hours a day 5 days a week; and throughout most of that period, my left hand was in a cast. I only mention it here for the purpose of time estimation - it took me significantly longer to accomplish even basic fabrication steps and machine set-up.
The LTR Design
As mentioned earlier, the Lock to Rear or LTR design is not entirely unique. A number of years ago, there were at least two companies in the U.S. that marketed similarly configured muzzleloaders. As far as I know, these were both in-line percussion designs. From the limited available data, it appears they were less than effective at their intended purpose. I can also assume they disappeared as a result of the designs themselves - they simply did not attract many black powder traditionalists.
Unfortunately, this design won't change a traditionalist's perspective. One of my friends called it a monstrosity of the flintlock world - or, the bastard creation of Franken-Tech, seriously or jokingly I couldn't really tell. But once they actually held it, or watched it shoot, they seemed to warm to the creation.
Similar to any muzzleloader, this design incorporates standard off-the-shelf components. This includes the lock, barrel and various minor parts. They are simply arranged differently, in a custom configuration that is unique, and within the limits of the individual components. There is one notable difference in this design;
The custom trigger mechanism is assembled to a sled that houses the trigger, connecting rod, trip arm, springs, adjusters and linkages. Both the pistol grip and lower butt-stock are also attached to this component. The design also allows the user to adjust the two-stage trigger pull anywhere between 1/2 to 7lbs - and overall pull ultimately turned out much smoother than expected. It actually rivals some of my set triggers on other flintlocks I own. The sled can be easily removed to clean, adjust or repair the mounted components.
Of all components, 60% are custom built and represent the majority of fabrication time and effort.
All my scratch-built rifle designs have started with a scale drawing. It is best, IMO, to ultimately design everything in a 1:1 scale. This takes-up more room on paper, but is a more accurate representation of what I was going to end-up with. My fabrication issues were more evident than in a scaled-down drawing. I just use large size standard graph paper, and tape several together when required.
Major Component Selection / Fabrication
I have to mention here that my largest resource for components and fabrication advice will always be the organization and people at Track of the Wolf. They are, in my opinion, the best around for anyone attempting any scratch build. My hat comes off to them, and I owe a portion of my success in this project to their incredible customer service, resource material and down to earth advice.
Major off-the-shelf component selection involved a fair amount of searching, analysis & investigation. Once completed, I ultimately selected the following;
1. Track of the Wolf gun-makers lock - A Siler Style lock with oversize plate,
2. Standard musket style trigger, (heavily modified),
3. Custom 31" .45 cal barrel (twist is 1 turn in 48 inches) Octagon with straight tang breech plug, (from a barrel maker in Tennessee, who's name escapes me now).
4. Full-length Walnut stock blank, (from my neighbours' Walnut tree that fell two years ago).
The original octagon-shaped barrel was turned-down on a lathe to a full-length 1" round. This achieves a couple of things; it is easier to inlay, and easier to full-length glass bed. It also works and looks better for this particular design.
The original full-length stock blank was first modified by cutting-off a 28" length of the fore-stock. This becomes the newly defined main-stock for the LTR. The remaining butt-stock wood and various rectangular pieces of remaining Walnut are used to construct the hand-guard, pistol grip, grip guard and lower butt-stock.
Using a router table, the main-stock and hand-guard are inlayed for the barrel channel. The hand-guard was then sanded to shape on a belt sander using a medium grit abrasive.
Making the basic barrel channel using the router table takes several passes at small, incremental depths. Walnut is very hard, and dulls even the most expensive router bits quickly. This had to be a slow, methodical operation which resulted in a very good fit.
The next operation was to fit the barrel breech and breech-plug tang to the main-stock. The first process is to square-off the rounded-end of the channel using standard chisels and a little patience.
The next step was to insert the breech plug, and remove the required material in order for it to fit with the barrel resting on the bottom of the barrel channel. This is done the old fashioned way, using chisels a hammer and slow, systematic removal of material. You will note that the tang sits higher than the top of the main-stock. This requires cutting a channel and epoxying a block of Walnut that the tang is fastened to. This block essentially becomes the recoil lug, and both the breech and tang will be bedded to it for a solid fit.
This was the best way to get this particular result; all my other options would have resulted in wasted material, or more complex operations.
The pistol grip was three pieces of laminated Walnut, shaped to fit my hand perfectly. A very good set of miniature wood rasps is essential to complete this task satisfactorily. The best way to achieve a perfect fit is to first squeeze a large enough lump of modelling clay, leaving an imprint of your grip. Simply use this as a template for forming your pistol grip.
Once all the above fabrication operations were completed, I ended-up with all the basic components; Barrel, hand-guard, and grip guard (not pictured) main-stock, pistol grip and lower butt-stock in their basic configurations. Note that both the lower butt-stock and pistol grip in this image are going to go through a couple of changes before the final assembly.
The next operation was the fitting of the hand-guard to the breech-plug tang. The purpose of the hand-guard is more for comfort, as you will see later. The hand-guard is also important to the function of the flint shield. This is a significant safety component that will be fabricated at a later time. However, it is important to note that due to the LTR design, the lock sits to the right-side of the shooters face, as opposed to several inches to the right front (for RH rifles) of the shooters eyes. The flint-shield protects the shooters face and eyes from flash, flint shrapnel and powder residue upon firing. In my experience and opinion, this design aspect vastly improves safety when compared to traditional flint-lock rifles.
The hand-guard also imparts more of a military look and feel to the finished product. I used the milling machine to achieve more precision.
Next was the bending and fitting of the trigger sled. This is essentially a strip of 1.25" w x 1/8" thick stainless steel that attaches to the main-stock from the bottom using screws. All the trigger components, pistol grip, grip guard and lower butt-stock are mounted to the trigger sled.
The stainless steel is bent using a very simple but effective process. A Vice-Brake can be purchased or built, both achieve the same results. One side consists of a V block; the other side is a inverted V or U receiver. Here I use two pieces of angle-iron, carefully positioned to hold the material. Draw a line on the material where you want it bent; place the line on the V block; then close the vice firmly. Assuming everything was aligned correctly, you will get a perfect 90 degree bend.
The trigger sled must now be inlayed to the main-stock. This initial step is a relatively simple process, where the milling machine is once again a perfect tool for the job.
After pencilling the outline of the trigger-sled against the underside of the main-stock, the stock is then set in the mill. Using a 1/2" end-mill, 1/8" depth of Walnut is removed on two sides. Corners are cleaned-up using a small chisel.
Here is the test layout of trigger sled, main stock, pistol grip and lower butt stock.
At this point it time, I decided that I needed to plane-down the main stock and lower butt stock to a uniform thickness, and shape the main stock fore grip. Although I should have done it before inlaying the trigger sled, as it did result in a nasty chip. Although now repaired.....it pissed me off royally. Lesson learned.
Here I use a series of rasps to shape the fore grip; sand paper does the rest of the work. Once again, the milling machine is used to create the finger channels on the fore grip. Note that you can use router tooling in a milling machine to perform work on hardwoods. Slower speeds seem to work better, and result in very clean cuts.
As mentioned previously, the lower butt stock was redesigned - for a number of reasons. First, it simply didn't feel right when against my shoulder; second, it was heavier than it needed to be, and finally - it needed to be a component easily removed in order to access the travel adjustment for the trip lever.
This was the re-design process for the lower butt stock, with the required split guards. The split guards are simply metal pieces over wood that prevent the hard wood from splitting (under load) when using multiple wood screws across the same grain line. Once again, I use a strip of stainless steel which will be drilled and countersunk for the 2" screws required.
I used a piece of Delsan ($5 from a local surplus store) to make the buttplate. I simply cut a block on the bandsaw, and shaped it on the mill. One of the interesting properties of this material is that you simply heat it with a pencil torch after you’ve finished cutting & sanding it to shape, and you get a really nice, sealed finish; almost like it was moulded.
The trigger sled must now go through further fabrication and assembly with all trigger and grip components attached. There are over twenty holes (1/2 of them are threaded) and multiple slots required in the sled in order to mount the required components and attach it to the main stock. This is an involved process, and required patience. Any minor deviance would have resulted in improper alignment of the components, and it wouldn't have worked as it was supposed to.
The sled is designed with one connecting rod from the trigger to an L-shaped (trip) lever. The connecting rod pulls (when the trigger is pulled), on the trip lever that rotates and pushes up on the sear arm of the lock, releasing the ####. There are simple mathematical equations to calculate the ideal sized lever, for the force required to trip the sear on the lock. The following formula was used to help design the trip lever and connecting rod system.
IMA = 2 x R1 / R1 - R2: AMA = FW / FL: Efficiency = AMA / IMA
Here you see the trigger sled, with the lower butt stock split guards marked alongside in order to ensure perfect alignment.
I must tell you that the effort required when working with stainless steel is significant. It is hard on machinery, tooling, and your patience. But it is the best material to use, in my opinion, for a black powder firearm, where corrosion can be a real problem.
Below are initial test cuts in scrap SS material for the required slots and countersink holes on the sled.
The next 2 pics are the processes in populating the sled with the trigger base after all the slots & holes, countersinks and threads were completed.
Fabrication of the trip lever is straightforward. Using the formula already mentioned, I cut-out & milled the aluminium lever after drilling for the bearing. The bearing was simply to ensure smooth operation under maximum load.
After the basic operations for the trip lever, the support brackets needed to be fabricated. They are 90 degree aluminium angle plates to support the lever on the sled; Simple & effective.
After aligning, drilling, tapping and making some final cuts & adjustments, here is the completed trip lever. You'll note that there is now an additional bearing on the upper lever surface; this is for the direct metal to metal contact to the hardened steel sear-arm on the lock.
The process continues with connection of the trip lever to the connecting rod, through the rod guide, installing the return spring, lock ring, trigger connector & lock nut.
As you probably figured out by now, the connector rod actually starts at the front top side of the sled, and ends-up at the underside of the rear. This was simply part of the design, allowing for maximum access and adjustability by the user - as well as meeting the lever/formula requirements. However, it also means that almost all wood components have a central channel cut in order to allow the components clearance to function, as well as keeping them enclosed in the main stock. Below is the lower trip lever channel configuration in the lower butt stock.
I should also mention that the original pistol grip has gone through one addition from the original design. I call the forward "L" shaped wood addition the "grip guard". It actually provides three functions; the first, is obviously a guard for the trigger. The second, and less obvious, is that it acts to prevent the pistol grip from twisting. Lastly, it imparts extra strength to the grip (which will get knocked around). I also think it gives it a very distinctive look and feel.
Here are two pics of the 80% finished trigger sled with all components attached.
Inlaying or channelling of the main stock is the next major fabrication step. This allows for fitting of the completed sled so the linkage components are enclosed and free to move. It is done completely on the milling machine for simplicity and accuracy.
Here is the main stock on the mill, with the trigger, connecting rod and return spring channels completed. On the right is the alignment test fit of sled, lower butt stock and main stock.
Because of the necessity of maintaining perfect alignment of components, regardless of how many times the unit might be dropped or user disassembled; all wood to metal contact is bedded using Brownells Acraglas Gel. This includes the sled, lock and barrel. Acraglas is marvellous stuff - and when properly used, does what it says. Here the sled is being prepared for bedding after all components have been removed.
Inlaying or seating the lock in the main stock is the next and most significant fabrication step. There are three critical areas in this design that must be achieved in this step. First is the alignment of the flash pan to the projected touch hole and/or touch hole liner location. Second, the alignment of the sear to the trip lever; and finally the alignment of the lock in relation to the barrel/barrel channel.
Before I started anything, with this new barrel - I had to determine where the touch hole needed to be in relation to the barrel and breech plug I was using. There are many schools of thought to this - but ultimately, in this flint-lock configuration, I wanted the touch-hole to be as close to the breech face as possible. I will be using 1/4"-32 tpi liner; which means I will locate the flash hole 1/8" from the breech face. This means that 1/8" of the liner will overlap the internal breech threads.
Once the touch-hole position was determined, the location of the flash-pan/lock is easily figured-out. I marked the main stock with a zero-datum flash-hole location line, and made any minor adjustments to the lock position as required.
The next step was to dismantle the lock in order to fit the lock plate without interference from the various lock parts. Once marked, the lines were scored with a very sharp knife at all cross-grain points on the cut-lines. This was to eliminate possible chipping from the cutting tool.
Once the main stock is marked, it's back to the milling machine to begin the inlaying operation. Slow and methodical was best, with frequent test fits between major cuts. First successful test fit on right without barrel inserted. Note relation of datum point (+) to bottom of flash pan.
Test fit with barrel inserted. Datum point, flash pan and vent hole location are aligned vertically. A good fit, although note that the horizontal line on the barrel should bisect the top of the flash pan edge. It is about 1/8" too high for proper touch-hole positioning for this Siler lock.
Inlaying detail, lock removed.
Fully assembled lock inserted, and function tested for clearance of all internal and external components. Note the block of Walnut as a "flint" - this allows complete function testing without unnecessary wear to the frizzen.
The next step is to set the lock, by drilling through both the lock & upper butt stock & tapping the lock-plate. Alignment is critical, which is why both are drilled at the same time.
Now that the lock, upper butt stock and barrel are aligned, it's time to drill the touch hole, and install the vent liner. Not very complicated, but not paying attention and a person can ruin a barrel. The vent liner I used is 1/4 - 36.
Drilled and tapped, with the overall config on the right. Positioned exactly where it needs to be for efficient ignition with this Siler lock.
Now that the rifle is vented, it's time to build the flint shield and attach it to the hand guard. In this design, the flash pan is close to the face, (behind the eye's), so it is critical that the flash pan be isolated.
The shield is unique; not only does it protect the shooter from the flash, flint shrapnel and powder residue, it also acts as a protective cover for inclement weather. I built a small release button, and the shield is also spring loaded to keep it closed. It easily folds forward, out of the way for priming or setting the lock.
I bent a 6" x 6" piece of aluminium into a U shape, and then epoxied and press pinned it together with several pieces of Walnut. Here are pics of the major steps I took to fabricate it & attach it to the hand guard.
The next step was purely cosmetic. I wanted the hand guard vented - simply because I thought it would add a little something to the overall LTR look.
Like many things when building anything from scratch, I required another alignment tool which I fabricated from a piece of aluminium. Here the hand guard is marked with the tool, (on the left).
Next, using a 1/2" Forsner bit - I made 10 vent holes in the hand guard.
Attaching the sight rail and final finishing;
The last machine operation is the fitting of the sight rail. The rail is attached directly to the barrel for best possible alignment, accuracy and durability. This is done using 1/4 - 20 threaded trunnions, dovetailed directly onto the barrel surface. I cheated and used a laser to align the trunnions with the bore; but it could have been done with simple tools. The rail is from S&J hardware, with a couple of modifications in order to mount it on my configuration.
Holes are drilled trough the hand guard so that the trunnions may pass-through to support the rail. Test fit of the rail, hand guard and flint shield prior to the finishing operations.
Prior to start of the finishing operation, I laid out all the parts for documentation/cataloguing purposes. The rifle is comprised of over 70 parts, and is quite a bit more complicated than most rifles of the same genre. Steel, stainless steel, aluminium and wood make-up 99.9% of this rifle, with only the butt plate & small linkage made of polycarbonates.
Here are the final assembly tests, (minus sight rail) prior to the various finishing / polishing operations. I made minor adjustments, trimming and tuning at this point.
The finishing steps are self explanatory. Lots of metal polishing and wood sanding with both paper, steel wool, sanding pads and polishing tools; took me about a week to complete. I used polymerized Tung Oil as a wood finish. Excellent stuff, with an awesome deep finish that isn't represented well in these pics.
After over a year of planning, design and fabrication - here is the finished Product. The pics really don't do it justice.
I slapped a cheap scope on, just for the first test firing as I had no other sights yet. The LTR will ultimately be equipped with blade front and rear peep sites for most of my summertime shooting. But with the rail, versatility is the word - anything can be put on.
Conclusions
This is a very utilitarian flintlock rifle with no pretty details or beauty marks. It is incredibly well-balanced, built tough and a real pleasure to shoot off-hand - the type of shooting it was designed for. After proofing, 3 loads were fired to test function. All touched-off perfectly, and very quickly. Developing loads & accuracy testing will occupy my summer.
The flint shield works better than I had anticipated - incredibly well as a matter of fact. It creates the odd sensation that you're not firing a flintlock, as it muffles both the mechanical noises, and flash.
Trigger pull is, well.....exactly what I wanted. Two stage like an Enfield rifle, with stage 2 set at a 4.7 - 5.0 lb release; crisp let-off with no creep at all.
It's a little heavier than designed, due to some of the additional stainless steel used - 8.6 lbs total (4.9 lbs is the barrel only), but most of the weight is between my shoulder and trigger hand. I can hold it as steady as a rock, with very little effort from my left hand/arm to keep it that way.
I'll file a range report with load data later on this summer. I hope you've enjoyed the posts. Feel free to drop me a PM (or e-mail) if you have any specific questions on the build. Oh, if you were wondering; total cost for components was approx $525. Actual labour time was approx 150 hrs.
Cheers!
W/Tech
End
I thought I would post my black powder winter build project. This is my tenth rifle build, and the first one that I documented from start to finish. It’s also my second non-traditional build – an all original design built from scratch.
This is a design that resulted from a couple of factors; first and most importantly, I can no longer support the forward weight of a traditionally designed muzzleloader due to surgery on my left hand/wrist last year. Secondly, I wanted to cross pollinate a rifle design from my experience as a tech in the military as well as my black powder build experiences with muskets, rifles and cannon.
The overall design itself may seem familiar and that term bull-pup will pop into any firearms enthusiast immediately. By its very definition, it's a term that I have decided not to use when referring to this flintlock design. Instead, I will use the terminology lock-to-rear or LTR flintlock. As this is the first version of this design, with three design revisions - it is designated as the Mark 1, Revision C, or LTR Mk 1c.
Design, planning and component prototyping began in early 2010, and took a total of eight months off and on. Most of the fabrication work took 10 weeks for several hours a day 5 days a week; and throughout most of that period, my left hand was in a cast. I only mention it here for the purpose of time estimation - it took me significantly longer to accomplish even basic fabrication steps and machine set-up.
The LTR Design
As mentioned earlier, the Lock to Rear or LTR design is not entirely unique. A number of years ago, there were at least two companies in the U.S. that marketed similarly configured muzzleloaders. As far as I know, these were both in-line percussion designs. From the limited available data, it appears they were less than effective at their intended purpose. I can also assume they disappeared as a result of the designs themselves - they simply did not attract many black powder traditionalists.
Unfortunately, this design won't change a traditionalist's perspective. One of my friends called it a monstrosity of the flintlock world - or, the bastard creation of Franken-Tech, seriously or jokingly I couldn't really tell. But once they actually held it, or watched it shoot, they seemed to warm to the creation.
Similar to any muzzleloader, this design incorporates standard off-the-shelf components. This includes the lock, barrel and various minor parts. They are simply arranged differently, in a custom configuration that is unique, and within the limits of the individual components. There is one notable difference in this design;
The custom trigger mechanism is assembled to a sled that houses the trigger, connecting rod, trip arm, springs, adjusters and linkages. Both the pistol grip and lower butt-stock are also attached to this component. The design also allows the user to adjust the two-stage trigger pull anywhere between 1/2 to 7lbs - and overall pull ultimately turned out much smoother than expected. It actually rivals some of my set triggers on other flintlocks I own. The sled can be easily removed to clean, adjust or repair the mounted components.
Of all components, 60% are custom built and represent the majority of fabrication time and effort.
All my scratch-built rifle designs have started with a scale drawing. It is best, IMO, to ultimately design everything in a 1:1 scale. This takes-up more room on paper, but is a more accurate representation of what I was going to end-up with. My fabrication issues were more evident than in a scaled-down drawing. I just use large size standard graph paper, and tape several together when required.
Major Component Selection / Fabrication
I have to mention here that my largest resource for components and fabrication advice will always be the organization and people at Track of the Wolf. They are, in my opinion, the best around for anyone attempting any scratch build. My hat comes off to them, and I owe a portion of my success in this project to their incredible customer service, resource material and down to earth advice.
Major off-the-shelf component selection involved a fair amount of searching, analysis & investigation. Once completed, I ultimately selected the following;
1. Track of the Wolf gun-makers lock - A Siler Style lock with oversize plate,
2. Standard musket style trigger, (heavily modified),
3. Custom 31" .45 cal barrel (twist is 1 turn in 48 inches) Octagon with straight tang breech plug, (from a barrel maker in Tennessee, who's name escapes me now).
4. Full-length Walnut stock blank, (from my neighbours' Walnut tree that fell two years ago).
The original octagon-shaped barrel was turned-down on a lathe to a full-length 1" round. This achieves a couple of things; it is easier to inlay, and easier to full-length glass bed. It also works and looks better for this particular design.
The original full-length stock blank was first modified by cutting-off a 28" length of the fore-stock. This becomes the newly defined main-stock for the LTR. The remaining butt-stock wood and various rectangular pieces of remaining Walnut are used to construct the hand-guard, pistol grip, grip guard and lower butt-stock.
Using a router table, the main-stock and hand-guard are inlayed for the barrel channel. The hand-guard was then sanded to shape on a belt sander using a medium grit abrasive.
Making the basic barrel channel using the router table takes several passes at small, incremental depths. Walnut is very hard, and dulls even the most expensive router bits quickly. This had to be a slow, methodical operation which resulted in a very good fit.
The next operation was to fit the barrel breech and breech-plug tang to the main-stock. The first process is to square-off the rounded-end of the channel using standard chisels and a little patience.
The next step was to insert the breech plug, and remove the required material in order for it to fit with the barrel resting on the bottom of the barrel channel. This is done the old fashioned way, using chisels a hammer and slow, systematic removal of material. You will note that the tang sits higher than the top of the main-stock. This requires cutting a channel and epoxying a block of Walnut that the tang is fastened to. This block essentially becomes the recoil lug, and both the breech and tang will be bedded to it for a solid fit.
This was the best way to get this particular result; all my other options would have resulted in wasted material, or more complex operations.
The pistol grip was three pieces of laminated Walnut, shaped to fit my hand perfectly. A very good set of miniature wood rasps is essential to complete this task satisfactorily. The best way to achieve a perfect fit is to first squeeze a large enough lump of modelling clay, leaving an imprint of your grip. Simply use this as a template for forming your pistol grip.
Once all the above fabrication operations were completed, I ended-up with all the basic components; Barrel, hand-guard, and grip guard (not pictured) main-stock, pistol grip and lower butt-stock in their basic configurations. Note that both the lower butt-stock and pistol grip in this image are going to go through a couple of changes before the final assembly.
The next operation was the fitting of the hand-guard to the breech-plug tang. The purpose of the hand-guard is more for comfort, as you will see later. The hand-guard is also important to the function of the flint shield. This is a significant safety component that will be fabricated at a later time. However, it is important to note that due to the LTR design, the lock sits to the right-side of the shooters face, as opposed to several inches to the right front (for RH rifles) of the shooters eyes. The flint-shield protects the shooters face and eyes from flash, flint shrapnel and powder residue upon firing. In my experience and opinion, this design aspect vastly improves safety when compared to traditional flint-lock rifles.
The hand-guard also imparts more of a military look and feel to the finished product. I used the milling machine to achieve more precision.
Next was the bending and fitting of the trigger sled. This is essentially a strip of 1.25" w x 1/8" thick stainless steel that attaches to the main-stock from the bottom using screws. All the trigger components, pistol grip, grip guard and lower butt-stock are mounted to the trigger sled.
The stainless steel is bent using a very simple but effective process. A Vice-Brake can be purchased or built, both achieve the same results. One side consists of a V block; the other side is a inverted V or U receiver. Here I use two pieces of angle-iron, carefully positioned to hold the material. Draw a line on the material where you want it bent; place the line on the V block; then close the vice firmly. Assuming everything was aligned correctly, you will get a perfect 90 degree bend.
The trigger sled must now be inlayed to the main-stock. This initial step is a relatively simple process, where the milling machine is once again a perfect tool for the job.
After pencilling the outline of the trigger-sled against the underside of the main-stock, the stock is then set in the mill. Using a 1/2" end-mill, 1/8" depth of Walnut is removed on two sides. Corners are cleaned-up using a small chisel.
Here is the test layout of trigger sled, main stock, pistol grip and lower butt stock.
At this point it time, I decided that I needed to plane-down the main stock and lower butt stock to a uniform thickness, and shape the main stock fore grip. Although I should have done it before inlaying the trigger sled, as it did result in a nasty chip. Although now repaired.....it pissed me off royally. Lesson learned.
Here I use a series of rasps to shape the fore grip; sand paper does the rest of the work. Once again, the milling machine is used to create the finger channels on the fore grip. Note that you can use router tooling in a milling machine to perform work on hardwoods. Slower speeds seem to work better, and result in very clean cuts.
As mentioned previously, the lower butt stock was redesigned - for a number of reasons. First, it simply didn't feel right when against my shoulder; second, it was heavier than it needed to be, and finally - it needed to be a component easily removed in order to access the travel adjustment for the trip lever.
This was the re-design process for the lower butt stock, with the required split guards. The split guards are simply metal pieces over wood that prevent the hard wood from splitting (under load) when using multiple wood screws across the same grain line. Once again, I use a strip of stainless steel which will be drilled and countersunk for the 2" screws required.
I used a piece of Delsan ($5 from a local surplus store) to make the buttplate. I simply cut a block on the bandsaw, and shaped it on the mill. One of the interesting properties of this material is that you simply heat it with a pencil torch after you’ve finished cutting & sanding it to shape, and you get a really nice, sealed finish; almost like it was moulded.
The trigger sled must now go through further fabrication and assembly with all trigger and grip components attached. There are over twenty holes (1/2 of them are threaded) and multiple slots required in the sled in order to mount the required components and attach it to the main stock. This is an involved process, and required patience. Any minor deviance would have resulted in improper alignment of the components, and it wouldn't have worked as it was supposed to.
The sled is designed with one connecting rod from the trigger to an L-shaped (trip) lever. The connecting rod pulls (when the trigger is pulled), on the trip lever that rotates and pushes up on the sear arm of the lock, releasing the ####. There are simple mathematical equations to calculate the ideal sized lever, for the force required to trip the sear on the lock. The following formula was used to help design the trip lever and connecting rod system.
IMA = 2 x R1 / R1 - R2: AMA = FW / FL: Efficiency = AMA / IMA
Here you see the trigger sled, with the lower butt stock split guards marked alongside in order to ensure perfect alignment.
I must tell you that the effort required when working with stainless steel is significant. It is hard on machinery, tooling, and your patience. But it is the best material to use, in my opinion, for a black powder firearm, where corrosion can be a real problem.
Below are initial test cuts in scrap SS material for the required slots and countersink holes on the sled.
The next 2 pics are the processes in populating the sled with the trigger base after all the slots & holes, countersinks and threads were completed.
Fabrication of the trip lever is straightforward. Using the formula already mentioned, I cut-out & milled the aluminium lever after drilling for the bearing. The bearing was simply to ensure smooth operation under maximum load.
After the basic operations for the trip lever, the support brackets needed to be fabricated. They are 90 degree aluminium angle plates to support the lever on the sled; Simple & effective.
After aligning, drilling, tapping and making some final cuts & adjustments, here is the completed trip lever. You'll note that there is now an additional bearing on the upper lever surface; this is for the direct metal to metal contact to the hardened steel sear-arm on the lock.
The process continues with connection of the trip lever to the connecting rod, through the rod guide, installing the return spring, lock ring, trigger connector & lock nut.
As you probably figured out by now, the connector rod actually starts at the front top side of the sled, and ends-up at the underside of the rear. This was simply part of the design, allowing for maximum access and adjustability by the user - as well as meeting the lever/formula requirements. However, it also means that almost all wood components have a central channel cut in order to allow the components clearance to function, as well as keeping them enclosed in the main stock. Below is the lower trip lever channel configuration in the lower butt stock.
I should also mention that the original pistol grip has gone through one addition from the original design. I call the forward "L" shaped wood addition the "grip guard". It actually provides three functions; the first, is obviously a guard for the trigger. The second, and less obvious, is that it acts to prevent the pistol grip from twisting. Lastly, it imparts extra strength to the grip (which will get knocked around). I also think it gives it a very distinctive look and feel.
Here are two pics of the 80% finished trigger sled with all components attached.
Inlaying or channelling of the main stock is the next major fabrication step. This allows for fitting of the completed sled so the linkage components are enclosed and free to move. It is done completely on the milling machine for simplicity and accuracy.
Here is the main stock on the mill, with the trigger, connecting rod and return spring channels completed. On the right is the alignment test fit of sled, lower butt stock and main stock.
Because of the necessity of maintaining perfect alignment of components, regardless of how many times the unit might be dropped or user disassembled; all wood to metal contact is bedded using Brownells Acraglas Gel. This includes the sled, lock and barrel. Acraglas is marvellous stuff - and when properly used, does what it says. Here the sled is being prepared for bedding after all components have been removed.
Inlaying or seating the lock in the main stock is the next and most significant fabrication step. There are three critical areas in this design that must be achieved in this step. First is the alignment of the flash pan to the projected touch hole and/or touch hole liner location. Second, the alignment of the sear to the trip lever; and finally the alignment of the lock in relation to the barrel/barrel channel.
Before I started anything, with this new barrel - I had to determine where the touch hole needed to be in relation to the barrel and breech plug I was using. There are many schools of thought to this - but ultimately, in this flint-lock configuration, I wanted the touch-hole to be as close to the breech face as possible. I will be using 1/4"-32 tpi liner; which means I will locate the flash hole 1/8" from the breech face. This means that 1/8" of the liner will overlap the internal breech threads.
Once the touch-hole position was determined, the location of the flash-pan/lock is easily figured-out. I marked the main stock with a zero-datum flash-hole location line, and made any minor adjustments to the lock position as required.
The next step was to dismantle the lock in order to fit the lock plate without interference from the various lock parts. Once marked, the lines were scored with a very sharp knife at all cross-grain points on the cut-lines. This was to eliminate possible chipping from the cutting tool.
Once the main stock is marked, it's back to the milling machine to begin the inlaying operation. Slow and methodical was best, with frequent test fits between major cuts. First successful test fit on right without barrel inserted. Note relation of datum point (+) to bottom of flash pan.
Test fit with barrel inserted. Datum point, flash pan and vent hole location are aligned vertically. A good fit, although note that the horizontal line on the barrel should bisect the top of the flash pan edge. It is about 1/8" too high for proper touch-hole positioning for this Siler lock.
Inlaying detail, lock removed.
Fully assembled lock inserted, and function tested for clearance of all internal and external components. Note the block of Walnut as a "flint" - this allows complete function testing without unnecessary wear to the frizzen.
The next step is to set the lock, by drilling through both the lock & upper butt stock & tapping the lock-plate. Alignment is critical, which is why both are drilled at the same time.
Now that the lock, upper butt stock and barrel are aligned, it's time to drill the touch hole, and install the vent liner. Not very complicated, but not paying attention and a person can ruin a barrel. The vent liner I used is 1/4 - 36.
Drilled and tapped, with the overall config on the right. Positioned exactly where it needs to be for efficient ignition with this Siler lock.
Now that the rifle is vented, it's time to build the flint shield and attach it to the hand guard. In this design, the flash pan is close to the face, (behind the eye's), so it is critical that the flash pan be isolated.
The shield is unique; not only does it protect the shooter from the flash, flint shrapnel and powder residue, it also acts as a protective cover for inclement weather. I built a small release button, and the shield is also spring loaded to keep it closed. It easily folds forward, out of the way for priming or setting the lock.
I bent a 6" x 6" piece of aluminium into a U shape, and then epoxied and press pinned it together with several pieces of Walnut. Here are pics of the major steps I took to fabricate it & attach it to the hand guard.
The next step was purely cosmetic. I wanted the hand guard vented - simply because I thought it would add a little something to the overall LTR look.
Like many things when building anything from scratch, I required another alignment tool which I fabricated from a piece of aluminium. Here the hand guard is marked with the tool, (on the left).
Next, using a 1/2" Forsner bit - I made 10 vent holes in the hand guard.
Attaching the sight rail and final finishing;
The last machine operation is the fitting of the sight rail. The rail is attached directly to the barrel for best possible alignment, accuracy and durability. This is done using 1/4 - 20 threaded trunnions, dovetailed directly onto the barrel surface. I cheated and used a laser to align the trunnions with the bore; but it could have been done with simple tools. The rail is from S&J hardware, with a couple of modifications in order to mount it on my configuration.
Holes are drilled trough the hand guard so that the trunnions may pass-through to support the rail. Test fit of the rail, hand guard and flint shield prior to the finishing operations.
Prior to start of the finishing operation, I laid out all the parts for documentation/cataloguing purposes. The rifle is comprised of over 70 parts, and is quite a bit more complicated than most rifles of the same genre. Steel, stainless steel, aluminium and wood make-up 99.9% of this rifle, with only the butt plate & small linkage made of polycarbonates.
Here are the final assembly tests, (minus sight rail) prior to the various finishing / polishing operations. I made minor adjustments, trimming and tuning at this point.
The finishing steps are self explanatory. Lots of metal polishing and wood sanding with both paper, steel wool, sanding pads and polishing tools; took me about a week to complete. I used polymerized Tung Oil as a wood finish. Excellent stuff, with an awesome deep finish that isn't represented well in these pics.
After over a year of planning, design and fabrication - here is the finished Product. The pics really don't do it justice.
I slapped a cheap scope on, just for the first test firing as I had no other sights yet. The LTR will ultimately be equipped with blade front and rear peep sites for most of my summertime shooting. But with the rail, versatility is the word - anything can be put on.
Conclusions
This is a very utilitarian flintlock rifle with no pretty details or beauty marks. It is incredibly well-balanced, built tough and a real pleasure to shoot off-hand - the type of shooting it was designed for. After proofing, 3 loads were fired to test function. All touched-off perfectly, and very quickly. Developing loads & accuracy testing will occupy my summer.
The flint shield works better than I had anticipated - incredibly well as a matter of fact. It creates the odd sensation that you're not firing a flintlock, as it muffles both the mechanical noises, and flash.
Trigger pull is, well.....exactly what I wanted. Two stage like an Enfield rifle, with stage 2 set at a 4.7 - 5.0 lb release; crisp let-off with no creep at all.
It's a little heavier than designed, due to some of the additional stainless steel used - 8.6 lbs total (4.9 lbs is the barrel only), but most of the weight is between my shoulder and trigger hand. I can hold it as steady as a rock, with very little effort from my left hand/arm to keep it that way.
I'll file a range report with load data later on this summer. I hope you've enjoyed the posts. Feel free to drop me a PM (or e-mail) if you have any specific questions on the build. Oh, if you were wondering; total cost for components was approx $525. Actual labour time was approx 150 hrs.
Cheers!
W/Tech
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