SA nm rear sight in M305 issue

Visleguy

Visleguy

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Hey everyone, I recently picked up a Springfield Armory NM rear sight to replace the original rear sight that came on my M305. For the life of me I cannot get them to seat properly within the receiver. After threading in the windage knob I can't get the elevation shaft in far enough to grab the screw on the windage knob. The only way to get it to seat after locating the flat spot takes persuasion on the elevation knob which ends up putting enough pressure on it that neither the elevation or windage knob are able to be turned. I've included a few pics to demonstrate the issue and was wondering if anyone else has come across this or knows of a solution to make these work. Is it the sight base? Anyways thanks for looking and info you can pass my way.

Original Norinco sights. This pic shows the gap between the elevation know and receiver right as the screw starts to bite and pulls it the rest of the way in.

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SA nm sight. Notice a much larger gap. This is were it needs to be tapped into the receiver to engage the screw and at this point locks up the whole sight. Dust cover is off but it's made no difference.

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Now, without the sight base in, the windage and elevation knobs go together just fine and function as they should.


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I'm on my blackberry but will look at your pics when I get home shortly.
Having fitment issues with a new SA NM rear sight as well.
Fits my LRB receiver just fine, having issues on a 2009 norinco.
My solution for the issues I'm having is to file and polish the receiver's sight ears to match the tighter tolerance of the SA's NM sight base.
The sight installed but with tension. However, trying to move it left or right caused binding of the base on the receiver ears.
Is yours doing the same?
 
It's common.
It takes some some serious fiddling to get the gears on the two pieces to line up with the gears on the peep sight.
All the while under the spring tension of the sight cover.
I did find this for you Sir:

http://www.fulton-armory.com/\faqs\M14-FAQs\NMRearSight.htm

I don't remember how I finally got mine to sit but I remember it took me a long time and a lot of swear words lol

Also to add this is a great one with good pics!

http://m14forum.com/reference/86160...ssembly-disassembly-adjustment-pic-heavy.html
 
Travis is right. I had a M305 with these same sights and it took some playing and a little bead of sweat that rolled off my temple to get everything fitted. It worked out though and was nice and tight.
 
You mention that you are using original Norinco windage and elevation knobs with this r. sight base. I don't know about the current Norinco r.sight units, but the earlier ones were somewhat dimensionally different than GI spec M14 and M1 Garand r. sight components. They were also softer. I've sometimes got them passed off as genuine GI parts and never found them to exchange properly with the GI components. I always discard them and stick to the GI spec parts. In this case you might want to assemble the readily available Garand parts (both knobs, aperture and cover) with this base.
 
45ACPKING said:
I'm on my blackberry but will look at your pics when I get home shortly.
Having fitment issues with a new SA NM rear sight as well.
Fits my LRB receiver just fine, having issues on a 2009 norinco.
My solution for the issues I'm having is to file and polish the receiver's sight ears to match the tighter tolerance of the SA's NM sight base.
The sight installed but with tension. However, trying to move it left or right caused binding of the base on the receiver ears.
Is yours doing the same?
Click to expand...

I thought about reaming the sight ears as well but as you can see in my last pic they fit just fine when I remove the sight base from the equation. I can get them installed but the tension is so great that neither elevation or windage are able to move at all. Almost like it's off centre to the sight ears. So in essence it sounds like we are having similar issues. Thanks.
 
Travis Bickle said:
It's common.
It takes some some serious fiddling to get the gears on the two pieces to line up with the gears on the peep sight.
All the while under the spring tension of the sight cover.
I did find this for you Sir:

http://www.fulton-armory.com/\faqs\M14-FAQs\NMRearSight.htm

I don't remember how I finally got mine to sit but I remember it took me a long time and a lot of swear words lol

Also to add this is a great one with good pics!

http://m14forum.com/reference/86160...ssembly-disassembly-adjustment-pic-heavy.html
Click to expand...

Lol yes a few bad words have been involved in this. Especially when the little screw and retainer popped out of the windage knob. Thanks for the links, I'll check them out. Cheers.
 
purple said:
You mention that you are using original Norinco windage and elevation knobs with this r. sight base. I don't know about the current Norinco r.sight units, but the earlier ones were somewhat dimensionally different than GI spec M14 and M1 Garand r. sight components. They were also softer. I've sometimes got them passed off as genuine GI parts and never found them to exchange properly with the GI components. I always discard them and stick to the GI spec parts. In this case you might want to assemble the readily available Garand parts (both knobs, aperture and cover) with this base.
Click to expand...

No im using the SA base with the SA windage and elevation knobs. The first pic (all Norinco parts) is just reference to show how far off I am in the second pic with the SA sight parts. You bring up a good point with the in or out of spec part though. I guess what I'm wondering is if the SA rear sight is out of spec or if it's the sight ears on the receiver. Thanks.
 
Well I read through the links (thanks Travis) and tried and tried again. No luck. Waaaaayyyy too tight. May just sum it up to a lesson learned and take purples advice and look for some usgi sights/parts. Thanks guys.

45ACPKING, if you get yours working properly I would love to hear what you did to accomplish it.
 
Where did the NM sight base come from? There are repros being sold that are off spec. The Kuhnhausen Shop Manual on the M1/M14, available from Brownells for $50, contains an excellent description of fitting up the rear sight assembly, incl NM parts. It can take quite a bit of tinkering and selective fitting of components to fit up a rear sight for improved accuracy. You can improve things a lot by selectively fitting an aperture and rear sight base to find a combination with minimal sideways movement of the aperture in the base. Installing a sight cover that provides tension/springback against the base/aperture when it is moved forward is desirable as well. Use a lot of grease in the interior rails of the base and hook a rubber band over the aperture and around the elevation knob when firing. These can help to keep things tight.
 
Travis Bickle said:
It's common.
It takes some some serious fiddling to get the gears on the two pieces to line up with the gears on the peep sight.
All the while under the spring tension of the sight cover.
I did find this for you Sir:

http://www.fulton-armory.com/\faqs\M14-FAQs\NMRearSight.htm

I don't remember how I finally got mine to sit but I remember it took me a long time and a lot of swear words lol

Also to add this is a great one with good pics!

http://m14forum.com/reference/86160...ssembly-disassembly-adjustment-pic-heavy.html
Click to expand...

i don't think the problem he is having is common at all
remember, m14forum and other American references are for American made parts ect, use the info, methods and advice for your LRB, M1A , JRA ect...... more often than not, the same info does not correlate to the same results with a Chinese rifle.

the problem I had with these sights (full NM assembly from spcamno) is the base does not fit the profile of the Chinese rear sight ears causing the base to bind and lift as it tries to ride over top of the ears.... on both sides.
it's not a spring cover issue, nor is it a common problem I've run into routinely. Like I said, the set fits my LRB receiver just fine
so, in my case, and relying on my experience building these rifles full time for the past decade , I found the problem was remedied by conforming the receiver ears to the sight base.
the amount of material to remove is very minor, it is not a major operation.
quite simple really ;)

look at OP's last pic , see the slight wear mark on the top of the right side receiver sight ear ? directly above the pinion? that is the binding I am talking about.
 
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mine was binding in same fashion on both sight ears. however, when I put it on my LRB receiver, zero problem...... that led me to the simplest explanation, the norinco receiver sight ears were just a hair oversize for the NM tolerances of the sights I was installing. also, seeing as how I have the Kuhnhaussen shop manual pretty much memorized, I found that the problem did not fall into the standard procedures nor advanced procedures of fitting/modifying parts to fit correctly...... so again..... I surmised, the problem lies in the dimensions of the sight ears of the receiver.
I am in the final stages of polishing and I have full side to side windage tracking, no binding, no tension change.
lucky for me this rig is going off to Frank at cerakote BC for a graphite black makeover when she's finished.




oh, I should add, I got these sights from Spcamno and they are very nice ;)
I wouldn't hesitate to grab another set , even if that meant having to follow the same fitting procedure.
a lot of folks cringe when they see "receiver modifications" but sometimes it is the correct route.
 
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45ACPKING said:
mine was binding in same fashion on both sight ears. however, when I put it on my LRB receiver, zero problem...... that led me to the simplest explanation, the norinco receiver sight ears were just a hair oversize for the NM tolerances of the sights I was installing. also, seeing as how I have the Kuhnhaussen shop manual pretty much memorized, I found that the problem did not fall into the standard procedures nor advanced procedures of fitting/modifying parts to fit correctly...... so again..... I surmised, the problem lies in the dimensions of the sight ears of the receiver.
I am in the final stages of polishing and I have full side to side windage tracking, no binding, no tension change.
lucky for me this rig is going off to Frank at cerakote BC for a graphite black makeover when she's finished.




oh, I should add, I got these sights from Spcamno and they are very nice ;)
I wouldn't hesitate to grab another set , even if that meant having to follow the same fitting procedure.
a lot of folks cringe when they see "receiver modifications" but sometimes it is the correct route.
Click to expand...

The hand fitting looks awesome I might need tips / help from you after I dust off both my Norincos to install these sights (lol).
 
Seafury said:
No what's awesome is the fine linens this gentleman uses to protect his rifles. Truly a conesieur of the type.
Click to expand...

LOL fine linens
actually, I'm laid up on the couch and fitting the sights at my coffee table watchin movies. took those pics beside me on the blanket on the couch
I took a serious work place injury as a bridgebuilder/steel fabricator back in 98 and this years moose hunting trip was especially hard on my body. not really walking much right now and the shop bench is just too far away right now LOL.
 
Okay, I'm in Madrid right now with free wireless so I might be able to chime in here with my iPhone.

Over the many years I've done the MM sight install, I've learned that with the contract USG I MM sights the thread pitch for the windage knob AND the NM marked base are a tighter pitch; go and have a look. I'm not joking.

The standard thread pitch is 16 turns per inch or tpi. Notice that they are coarse to obtain a single MOA point of impact shift per klik. Everybody with me so far ??

Now with the USGI contract NM sights; ensure that. BOTH your base and windage knob are NM marked and you can visibly identify that the thread pitch I warned you about is tighter than your typical pitch on the typical standard windage knob thread pitch.

The NM sights obtain the 1/2" MOA impact shrt by cutting the threads to a tighter pitch of 32 tpi as you likely guessed by now. My coach explained this to me back in 1987. Darn I'm getting old. So you young dudes better learn this shzt before I die one day, #####ez! :wave:

Go and do or verify that RFN (right now)!!! :)

Once you are pleased go ahead and pull off your Norinco rear sight assembly.

Install the spring cover and rear sight base and then the necessary aperture, hopefully it's NM marked as well.

Insert the elevation knob after greasing the engaging threads on the splines and the spindle threads. Just reduces the profanity level. :D

Ask me how I know. Yuk yuk yuk

Now here comes the harder part; grease the exterior threads that are visible on the windage knob and then grease lightly the interior barrel threads where you know the elevation knob spindle body will be inserted.

Pierre Elliot Trudeau asks Maggie ,"Is it in dear?"

Maggie replies," yes dear, Just IN!"

Get the old western Canada joke? I am from the west coast where we grew up hating Turdeau. :)

Okay ensure that when you install the windage knob into the rear sight base, be sensitive and careful NOT TO CROSS Thread this baby into the rear sight base otherwise yer #### will fall off! :eek:

Often I will dry run the installation outside the supporting rear sight ears WITH grease on all threads. Get that set of fine threads talking to each other FIRST.

Lemme guess; it's too late fer some of you right? :cool:

Well I hope you guys who encountered some difficulties go back, grease them threads and carefully CHASE the threads very lovingly.

That's the hard part.

I hope it's not to late for you M14 upgraders.

I'm bussing to The city of Granada for one night. I should have wireless at the hotel so I will cue back with you all tomorrow night. Gotta pack my duffel bag tonight.

Get that grease syringe out. I can always sell them to ya at my next clinic!

Cheers and be kind to those threads :wave:

Barney
 
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purple said:
Where did the NM sight base come from? There are repros being sold that are off spec. The Kuhnhausen Shop Manual on the M1/M14, available from Brownells for $50, contains an excellent description of fitting up the rear sight assembly, incl NM parts. It can take quite a bit of tinkering and selective fitting of components to fit up a rear sight for improved accuracy. You can improve things a lot by selectively fitting an aperture and rear sight base to find a combination with minimal sideways movement of the aperture in the base. Installing a sight cover that provides tension/springback against the base/aperture when it is moved forward is desirable as well. Use a lot of grease in the interior rails of the base and hook a rubber band over the aperture and around the elevation knob when firing. These can help to keep things tight.
Click to expand...
,

The rear sight was purchased here on the EE. Honestly have no idea where they actually came from. The funny or not so funny part is that I can assemble the SA parts with the Norinco base no problems but can't thread the Norinco windage knob into the SA base. I'll take some closer pics of the SA base in a bit here.
 
45ACPKING said:
mine was binding in same fashion on both sight ears. however, when I put it on my LRB receiver, zero problem...... that led me to the simplest explanation, the norinco receiver sight ears were just a hair oversize for the NM tolerances of the sights I was installing. also, seeing as how I have the Kuhnhaussen shop manual pretty much memorized, I found that the problem did not fall into the standard procedures nor advanced procedures of fitting/modifying parts to fit correctly...... so again..... I surmised, the problem lies in the dimensions of the sight ears of the receiver.
I am in the final stages of polishing and I have full side to side windage tracking, no binding, no tension change.
lucky for me this rig is going off to Frank at cerakote BC for a graphite black makeover when she's finished.
Click to expand...

Hmm, I'll take a closer look tonight but that may very well be the same problem I'm facing. Thanks for the pics.
 
I bought a NM sight here as well and had a difficult time getting it together but it did go and it is tight. Toight like a toiger. Now I have to take it apart and grind the angle on my apertures so I can exchange them without taking the sight completely apart. And Mr King of the 45 ACP how exactly do you suppose that moose feels about the hunt?
 
Seafury said:
I bought a NM sight here as well and had a difficult time getting it together but it did go and it is tight. Toight like a toiger. Now I have to take it apart and grind the angle on my apertures so I can exchange them without taking the sight completely apart. And Mr King of the 45 ACP how exactly do you suppose that moose feels about the hunt?
Click to expand...

that moose is pretty damn tasty that's all I know ;)
have a look at your receiver sight ears for wear marks, maybe yours is tight for the same reason as mine was? ya never know
 
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