Swapping M14 Bolts?

M

mcgaffey

New member
Rating - 100%
19   0   0
I have a Dominion Arms M14 (M305) with a USGI bolt. As I was shooting, the bolt came apart and the bolt internals fell out. I now only have the stripped bolt and the firing pin. I believe I have two options, either buy the internals and a bolt tool and try to reassemble the bolt, or buy a different complete bolt.
Question: If I was to buy another bolt, from a different M305, would it work correctly? Or would it would be better to buy the bolt tool and the internals?

I can get a new bolt cheaper than the bolt tool and internals.

Thanks!
 
1. You don't need a bolt tool, use Google.

2. Any new bolt will have to be properly lapped in and headspace checked

3. Send everything to M14Medic and have him assemble it.
 
Last edited:
I would try and figure out why your bolt spontaneously disassembled itself...

That said internals are not all that expensive, and a new bolt should be fitted to the receiver.

John
 
Thank you for the replies. I think I am going to get the internals from armtac. As for why it came apart, I have no idea. It had shot it on multiple occasions prior and it functioned with no problems. The previous owner had it tuned by one of the M14 doctors / experts.
 
What ammo were you shooting? I shot hundreds of brass cased ammo through my first older one (I have two of them) and once I started using the steel cased Nork ammo the ejector popped out twice and the bolt guts followed. My newer one hasn't done this.
 
The most common cause of this problem is the extractor post protruding below the bottom surface of the bolt. It can be ground to shorten it.

Lapping a bolt is a nice touch, but not necessary. What matters is that the bolt headspace properly.
 
purple said:
Lapping a bolt is a nice touch, but not necessary. What matters is that the bolt headspace properly.
Click to expand...

Don't give advice that is WRONG. A bolt needs to be lapped in to assure proper contact between bolt lugs an reciever. This is a must. You could sheer off a bolt lug if proper bolt lug/reciever contact is not maintained.
 
yomomma said:
Don't give advice that is WRONG. A bolt needs to be lapped in to assure proper contact between bolt lugs an reciever. This is a must. You could sheer off a bolt lug if proper bolt lug/reciever contact is not maintained.
Click to expand...

Interesting. 6,000,000 + Garands and 1,400,000 M14's were built without lapping anything. J.C. Garand did not seem to find it a "must".

Lapping bolts is a contentious point among many folks. The idea is sound if all parts are within manufacturing specifications. The problem arises when you attempt to fit a bolt to a worn receiver. Removing material from the bolt may remove the surface hardening which will accelerate wear and possibly lead to a catastrophic failure. Switching bolts adds another problem. Unless it is a new bolt, how can you be sure it has not been molested by a previous owner? A minuscule lug offset is not the end of the world. (if the bolt is new or not otherwise buggered with)
 
Last edited:
N-O-R-I-N-C-O. Would be my first reason to go above and beyond. A new replacement bolt is usually oversized to allow for the wear on the reciever, would be my second. Anyway I guess those hundreds of guys writing articles about proper lug contact had nothing better to do on a Friday night.
 
Last edited:
And...
. ,
What most do not consider is he fact that real USGI M14 and M1 receivers were machined to exacting profiles and dimensional tolerances requiring NO lapping because the bolt and receiver lugs were mirror images of each other (helical machined) . Most commercial receivers are flat machined to replicate the helical lead angle but not true form. This is easier for them but requires lapping for the two faces to contact each other evenly. These surfaces are often left to minimum or tight specs so once lapping is done headspace is also at correct depth.This practice is easier for the manufacturers to produce . I've not checked any current receivers so I'm not sure if any of the new offerings are closer than the previous ones.
Click to expand...
 
yomomma said:
N-O-R-I-N-C-O. Would be my first reason to go above and beyond. A new replacement bolt is usually oversized to allow for the wear on the reciever, would be my second. Anyway I guess those hundreds of guys writing articles about proper lug contact had nothing better to do on a Friday night.
Click to expand...

N-O-R-I-N-C-O? It would appear you are telling someone to do a questionable procedure to a product of dubious quality. As for all those hundreds of guys who write articles, how many designed a firearm? Now of that number, how many have had their design go into mass production?
 
When my extractor broke it sent all my parts out of the gun and into the sand, luckily I found them all. Could be that maybe this happened to you.
 
One year back in the nineties while competing with the M14 (TRW cost me $400) at Base Borden, I was shooting the 300 Yard Deliberate, single feeding from the magazine, I remember watching the bolt fly forward , stripping the round (handloaded) and watching the cartridge rear pry upwards on the extractor. :eek:

I could barely find all the parts (luckily) and reassembled the USGI bolt just in time for the next match 6, 300 Yard Snap match. What a shocker that was.....

Here's a blast from the past in 1995:





Mons East Range... the good old days...

Cheers , :wave:

Barney
 
m14medic.ca said:
Usually, it's around 10% on one lug, as much as 30% on the other.

I consider 25% on each lug to be minimum contact.

John
Click to expand...

That sure doesn't say much for quality control, but the good news is that we don't read much about bolt failures in stock Norincos. US GI M14s and M1 Garands were made with a huge number of machining operations and in-process gauging during manufacture and its unlikely that the good folks at Norinco could match this.

Bolt lapping wasn't a feature of Garand/M14 arsenal rebuilding. Kuhnhausen cautions about bolt lapping in M1/M14 barreled actions as it will always increase headspace to some extent.

For those that are into lapping, Brownells sells a set for the M1/M14 for $65 which has good reviews.
 
purple said:
That sure doesn't say much for quality control, but the good news is that we don't read much about bolt failures in stock Norincos. US GI M14s and M1 Garands were made with a huge number of machining operations and in-process gauging during manufacture and its unlikely that the good folks at Norinco could match this.

Bolt lapping wasn't a feature of Garand/M14 arsenal rebuilding. Kuhnhausen cautions about bolt lapping in M1/M14 barreled actions as it will always increase headspace to some extent.

For those that are into lapping, Brownells sells a set for the M1/M14 for $65 which has good reviews.
Click to expand...

I agree.

Lapping is only Something i generally do to ensure good bolt contact. Unless I'm installing a new barrel, then I lap quite a bit to ensure perfect contact before cutting the chamber.

The brownelles kit is a very nice addition to the tool kit, if you're working on "known good" US receivers, barrels and bolts. I have one, and find that when working on "Chinese spec" receivers and bolts, it it is just easier and quicker to swap bolts until you find one that fits properly while also giving good headspace and then lapping it a bit (the old fashioned way with out the lapping jigs) to get good contact while still achieving headspace no larger than 1.638".

It has also been my experience that you'll be lapping a bolt in for quite some time to enlarge HS .001"....

John
 
Lapping.... Pfffftt.
Just take the belt grinder and tig welder to the lugs....get that headspace correct at all costs lol.

 
You must log in or register to reply here.
Back
Top Bottom