Go Back   CMP Forums > CMP Sales > M1A/M14
Register FAQ Members List Calendar Mark Forums Read

Reply
 
Thread Tools Display Modes
  #1  
Old 12-20-2012, 10:02 AM
rattler rattler is offline
 
Join Date: Oct 2009
Location: Ohio
Posts: 198
Default Looking for opinions on this bolt face

Links fixed
Bought this some time ago, now wondering if it has been welded. Even if it's not been welded, is the face too eroded to be serviceable? Also, can the lugs be miced to determine whether the bolt has been lapped? I cannot find a good dimensional drawing of an M14 bolt, tried Kuhnhausen.











Last edited by rattler; 12-20-2012 at 10:48 AM.
Reply With Quote
  #2  
Old 12-20-2012, 10:14 AM
buckshot85 buckshot85 is offline
 
Join Date: Oct 2010
Location: Cowtown, Wis.
Posts: 2,739
Default

links don't work
Reply With Quote
  #3  
Old 12-20-2012, 11:02 AM
DougS DougS is offline
 
Join Date: Oct 2009
Location: Michigan
Posts: 571
Default

It is hard to tell, but it seems the bolt has honest wear and someone just reparked it. Have you checked the firing pin hole for size (.0785 or a #47 drill bit, ovesize is .082 or a #45 drill bit), and firing pin protusion?
Reply With Quote
  #4  
Old 12-20-2012, 11:35 AM
hammonje hammonje is offline
 
Join Date: Feb 2010
Location: Union, KY
Posts: 4,497
Default

Exactly....primer imprinting and just reparked. Notice the smoothness of the firing pin hole and ejector area. I'd use it in a heartbeat. Might take some jewelers rouge and polish the roller. I'm just anal about stuff like that though.

Loos good.
Reply With Quote
  #5  
Old 12-20-2012, 02:26 PM
M14 M14 is offline
 
Join Date: Jul 2011
Location: south mississippi
Posts: 874
Default

Quote:
Originally Posted by hammonje View Post
Exactly....primer imprinting and just reparked. Notice the smoothness of the firing pin hole and ejector area. I'd use it in a heartbeat. Might take some jewelers rouge and polish the roller. I'm just anal about stuff like that though.

Loos good.
Yep, I agree, it appears as normal for fired bolts. A lot of etching or erosion was allowed at the bolt face and around the firing pin hole, in the military, before replacement.

The measurements to see if it has been lapped, which is much difficult, because the specs have a .010 range on both sides, in any event, they are left side .450-.460 and right side, .560-.570 on the blueprint. I have seen many G.I. bolts that are .463 and .573 too. Mostly TRW, but an SA, and a Winchester, one each. I find the average is about .454 and .568, L & R sides respectively. Interestingly enough, I have never see an HR bolt over spec....and I have seen a lot of bolts.
Reply With Quote
  #6  
Old 12-20-2012, 02:39 PM
hammonje hammonje is offline
 
Join Date: Feb 2010
Location: Union, KY
Posts: 4,497
Default

Let her Rip!!!! Nice info. Thanks. Good to know.

Rip....what is the rationale for the wear patterns seen on bolt faces???? I always thought it looked an awful lot like the dimensions of the cartridge primer.
Reply With Quote
  #7  
Old 12-20-2012, 02:57 PM
rattler rattler is offline
 
Join Date: Oct 2009
Location: Ohio
Posts: 198
Default

Thanks everyone. The lugs measured .460 on left, and .572 on right. This is a reparked TRW bolt, which apparently is good to go. I thought same as hammonje, that the deepest circular mark on the face looked like gas erosion from leaky primer pockets. Is that the cause, Rip?
Reply With Quote
  #8  
Old 12-20-2012, 06:00 PM
M14 M14 is offline
 
Join Date: Jul 2011
Location: south mississippi
Posts: 874
Default

Quote:
Originally Posted by hammonje View Post
Let her Rip!!!! Nice info. Thanks. Good to know.

Rip....what is the rationale for the wear patterns seen on bolt faces???? I always thought it looked an awful lot like the dimensions of the cartridge primer.
Quote:
Originally Posted by rattler View Post
Thanks everyone. The lugs measured .460 on left, and .572 on right. This is a reparked TRW bolt, which apparently is good to go. I thought same as hammonje, that the deepest circular mark on the face looked like gas erosion from leaky primer pockets. Is that the cause, Rip?
Yeah, it was pretty common. Also keep in mind that the erosion as it appears irregular and uneven, was done under battlefield conditions on some. Add a little sand or dirt between the bolt face and the cartridge seat, and it is a recipe for erosion. Mix in a little leakage around the primer pocket, and the primer crimps sharp, brass edge, digging in as it is fired for hundreds of rounds, and you have a nice wear pattern on the face.

I have seen some H, that have the perfect imprint of the entire cartridge seat mashed into the bolt face.

I have used bolts that the erosion was so bad, that the outer ring appeared as a crack, but never had any problems with them. You could hang your fingernail in them. You have to picture what the molecular structure of the bolt looks like when it is hammer forged. It causes it to align with the way it was hammered.

I have stripped bolts before to the bare metal to refinish them, and the striations on top of the bolt were perpindicular to the length of the body. If that held true for the entire bolt, and it would because of the way they were hammered in the dies, then the bolt face would be the end grain, like in a tree. This may explain some of the erosion as not being so much just erosion, but stria of the grain as well.
Reply With Quote
  #9  
Old 12-25-2012, 10:06 AM
longunner longunner is offline
Banned
 
Join Date: Oct 2012
Location: NJ
Posts: 939
Default

rough mill... possible slightly dull bit. Gas leaks don't look like that.

Here's gas leaks.....

http://s649.beta.photobucket.com/use...30369567205763

Last edited by longunner; 12-25-2012 at 10:28 AM. Reason: post picture
Reply With Quote
  #10  
Old 12-25-2012, 11:41 AM
M14 M14 is offline
 
Join Date: Jul 2011
Location: south mississippi
Posts: 874
Default

Quote:
Originally Posted by longunner View Post
rough mill... possible slightly dull bit. Gas leaks don't look like that.

Here's gas leaks.....

http://s649.beta.photobucket.com/use...30369567205763
I disagree. Yours looks the same exact way, only advanced to a larger degree for depth. It looks like it had a good bit of erosion, rust, and sand to boot, mixed with an initial rough machining line. I will agree that leaks are rare and very small, but they add up over time.

For rattler- I would shoot it till it melted down in the rifle.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 08:49 PM.