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  #11  
Old 10-02-2012, 10:07 AM
M14 M14 is offline
 
Join Date: Jul 2011
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Quote:
Originally Posted by Roadkingtrax View Post
I'm just looking for supporting data that would suggest M1's have a serious setback issue.

So far, only commercial non-GI spec M1A's are of a concern at this point. People have a way of exacerbating a problem, and especially new shooters will grab on to an issue when it is not really a concern.

You point out that the contacting lugs help accuracy, and than suggest a serious risk to safety if they don't. Which one is more important? Certainly the data will point to the real reason.

Supporting data. Ok, how's this. I tell you there is, and was setback ( not setback, manufacturing). Three different receivers with numerous bolts to try, and all showing the same ratio to the receiver lugs, 40's to post war production. I have witnesses. Check yours and ask your friends to check theirs if you have any. That will give you the data you seek. I have proof, do you have proof of your assersions ? That it is not an issue or could not become one in an emergency ? NO, you don't.

No, commercial is not the only concern or I wouldn't waste my time writing all this or trying to get it through people like you's heads. Am I not explaining it clearly enough for you? I can assure you, I am not new to shooting, or the M1 or M14. I served as a range officer for 17 years, and have built 33 M14's and an uncounted number of M1's, so I think I know a little bit about what I write. If you do not consider a gap at the left lug a matter of concern, then by all means, keep shooting in blind bliss, and good luck with that. Just don't blow smoke at me and others here and tell us it is fog rolling in.

The ordinance gauge that the military used that indexed on the receiver bridge and the lugs was my guide, and was how I determined the left lug placement was off. I took the measurements from barrel ring datum to both and subtracted to find left lug spec on the receiver. This is the data, and points directly to the manufacturing as the reason.

And for the last time, I have never yet said it was a safety risk. Go back and read it again, I said "in the event" of an emergency type situation, such as an explosion like partial out of battery, slam fire, receiver, or barrel blow-ups, etc. etc.

Which one is more important, safety or accuracy ?.....jeez, I'm done trying to relate to you. That has got to be the dumbest question ever. Accuracy Of Course. So please, unless you have something to add that actually helps find more data, and doesn't spew dispersions on my character and insinuate I am making this up, then move on to someone else's threads and spread discontent there.

Hey Geeck, tell this gentleman that you were there and saw this with your own eyes. A crack big enough to throw a cat through. Then he can ask you for supporting data ! Then we can get Doc to post about all his I did with the same problem. But somehow I don't think that will satisfy him anyway. He will probably want a statement from the CMP saying that they pulled every last receiver in their inventory and put them on the ordinance gauge before selling them to the public, or at least a warning statement or instructional pamplet on how to fix this issue with them before firing. Should they do that ? Yes they should. Or I guess we can wait until some bottom feeder gets injured and the cause is traced to the left lug as having a gap and letting it fly apart, when if it had good contact, the guy might have been ok, then he sues the CMP and we all lose. Yeah, that's the ticket, we'll just let it go and not speak of it anymore. It does not exist, it does not exist, there is no supporting data, so it does not exist. Circular reasoning works because circular reasoning works because...................
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  #12  
Old 10-02-2012, 10:29 AM
mwhite49 mwhite49 is offline
 
Join Date: Oct 2010
Posts: 114
Default Lug issues

Thanks M14, very informative write up. My new LRB M25 is in the planning stages with almost all parts in hand and the builder you know well so I can at least rest assured it will be constructed correctly.
The point I think some are missing is that with ANY rifle that has a bolt with lugs on it was designed so that the lugs have a very large contact area to bear down on at the time of firing. And yes this lug contact is very important for 2 seperate issues, one being SAFETY, the other ACCURACY. Safety is the main overriding concern for all.
There are a some folks including Gun smiths putting together rifles like the M14 and even bolt guns who think barrel timing is the big issue, or correct threading of a new blank, and head space. A rifle may in fact head space just fine and well with in specifications but may have issues with lug contact. I have seen fired empties that M14 is talking about that are out of round. Some folks think this is caused by the round hitting part of the action on ejection. I think M14 nailed it as to the cause. Think of the lug contact as a timing issue. Both lugs should have 100% contact. If not then there should be an aceptable wear limit. I know my units Marine Armorer's went over our M14 with a fine toothed compb and they were all well used. My rifle had a new bolt put into it and I watched them lap it. During the process he explained why and how come. He knew I was a gun nut, I was also a Master Training Specalist teaching all kinds of weapons system to our troops and Nato troop for my last tour of duty before I retired. The reason I mentioned timing is that we used a set of TIMING Feeler gauges to set up our M2 .50 cal. each time it was torn down for cleaning, after each visit to the range, and in class. If timing was not an important issue we would not have covered it. The Amorer working on my shorty M14 ( cut off a the pistol grip) said that you know when you teach the guys about timing MA, well it the same on your M14. If the lugs do not get bedded in then there could be ejection issues, failure issues such as the action will fail to cycle, or more serious issues.
Do yourself, wives and kids a favour and check yours out. Hopefuly yours is OK.
Mike
USN Retired
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  #13  
Old 10-02-2012, 11:52 AM
hammonje hammonje is offline
 
Join Date: Feb 2010
Location: Union, KY
Posts: 4,499
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I am with Roadkingtrax on this issue and find bolt lug lapping to be over-rated big time. I have offered up similar questions in the past....why don't we lap in M1 Garand bolts???? Same old USGI receiver answer.

I simply grab some 400-600 grit lapping compound and use a Brownells M14/M1A bolt lapping tool. 20 turns and look at the bolt lug park removal. If better than 50% on both lugs I move on. Often it is better than 75%. It was better than that on many of my Fulton M14 receivers. I built 10 M14s this year and all (SAI, FA, HRA, WIN, TRW, and SA) bolts had better than 70% lug contact by this method. Seems as though lapping is over-rated.

Improves accuracy by squaring up the chambered round to the bore axis. How much this improves accuracy is multi-factorally dependent on numerous other items like stock fit, throat, bore condition, muzzle crown, ammunition, etc.

I guess it doesn't hurt, but one can't really quantify the improvement either. This being dependent on minimum lug contact that I set at 50%.
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  #14  
Old 10-02-2012, 01:29 PM
canes7 canes7 is offline
 
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Location: Raleigh, NC
Posts: 2,488
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If it's truly a safety issue the question would be how often and how much the right lug would have to be stressed in order for it to fail. For example you would have to take a bolt from heat lot x, cycle it y times with z amount of gap in the left lug to make it fail.

That would require new bolts of all different heat lots and scores of retireee's with nothing but time to do all the firing.

No way it's going to happen, the resources just are not there, and I'm thinking that's what the ordnance dept. came up with too.
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  #15  
Old 10-02-2012, 02:06 PM
ordmm ordmm is offline
 
Join Date: Oct 2009
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Quote:
Originally Posted by M14 View Post
No, commercial is not the only concern or I wouldn't waste my time writing all this or trying to get it through people like you's heads. Am I not explaining it clearly enough for you? I can assure you, I am not new to shooting, or the M1 or M14. I served as a range officer for 17 years, and have built 33 M14's and an uncounted number of M1's, so I think I know a little bit about what I write. If you do not consider a gap at the left lug a matter of concern, then by all means, keep shooting in blind bliss, and good luck with that. Just don't blow smoke at me and others here and tell us it is fog rolling in.


Which one is more important, safety or accuracy ?.....jeez, I'm done trying to relate to you. That has got to be the dumbest question ever. Accuracy Of Course. So please, unless you have something to add that actually helps find more data, and doesn't spew dispersions on my character and insinuate I am making this up, then move on to someone else's threads and spread discontent there.

Hey Geeck, tell this gentleman that you were there and saw this with your own eyes. A crack big enough to throw a cat through. Then he can ask you for supporting data ! Then we can get Doc to post about all his I did with the same problem. But somehow I don't think that will satisfy him anyway. He will probably want a statement from the CMP saying that they pulled every last receiver in their inventory and put them on the ordinance gauge before selling them to the public, or at least a warning statement or instructional pamplet on how to fix this issue with them before firing. Should they do that ? Yes they should. Or I guess we can wait until some bottom feeder gets injured and the cause is traced to the left lug as having a gap and letting it fly apart, when if it had good contact, the guy might have been ok, then he sues the CMP and we all lose. Yeah, that's the ticket, we'll just let it go and not speak of it anymore. It does not exist, it does not exist, there is no supporting data, so it does not exist. Circular reasoning works because circular reasoning works because...................

OK...I understand it now.
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  #16  
Old 10-02-2012, 02:07 PM
ramit ramit is offline
 
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Is ordmm deleting his own nasty rude comment posts in the thread that
we are getting the update notifications on, or is the Moderator...?

Last edited by ramit; 10-02-2012 at 03:51 PM.
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  #17  
Old 10-02-2012, 02:29 PM
ordmm ordmm is offline
 
Join Date: Oct 2009
Posts: 416
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Ramit,


Sorry you took offense. Deleted my post to M14. Won't happen again. Again, my apologies to all. Reread the post and have a better understanding of it now.

Last edited by ordmm; 10-02-2012 at 02:33 PM.
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  #18  
Old 10-02-2012, 02:37 PM
CaptainMagic CaptainMagic is offline
 
Join Date: Oct 2009
Location: Sunny Florida
Posts: 655
Default Hammonje

You must be talking about this M14 guy being rude right? All I've seen is M14 capping off on Roadkingtrax. I have no idea why ordmm deleted their post, it was spot on, I'd leave the room too.
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  #19  
Old 10-02-2012, 02:41 PM
CaptainMagic CaptainMagic is offline
 
Join Date: Oct 2009
Location: Sunny Florida
Posts: 655
Default Back on topic

Back on topic now, can anyone find a problem to help with the solution this post provides? I'm not sure that Roadkingtrax could have couched this better but I'll try, where's the beef?
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  #20  
Old 10-02-2012, 02:44 PM
d7cook d7cook is offline
 
Join Date: Mar 2011
Location: Ohio
Posts: 283
Default -

I've always found the % of contact thing odd. When you lap in a bolt all it's showing is the percent of area that the two surfaces sweep against each other when lapping. Not necessarily the percent of contact when in battery. I could theoretically lap a bolt to the edge of a razor blade and show 100% contact when done but in reality it's only resting on a razors edge when in battery.

With that said, whenever I put a bolt in anything M1 and M14 I at least mark the faces with a permanent marker and use valve lapping compound to check for contact. I think this is what RIP (M14) is saying. Your making sure you don't have excessive clearance on one side which would leave the bolt only hanging on by one bolt lug (the side that has contact).
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