PDA

View Full Version : Can a bolt face be rebuilt?


2_Grumpy
April 4, 2012, 06:37 AM
hi,

i have a m17 rechambered for .243. The face of the bolt has some pitting around the firing pin hole. The primer of a fired case expands into the pitting and then the extra length makes it difficult to insert in the reloading press.

So My question is, can the bolt face be built back up and machined to the right spec's or do I put up with it?

cheers

hooligan1
April 4, 2012, 06:43 AM
I'm sure it's possible, smiths talk about welding the firing pin hole closed and then redrilling it in true dead center, on some accurate rifle actions,,, hope this helps.
As far as where to send it? I'm not sure, I have'nt contacted any Gun Smiths in a long time, that did any work for me.

tango1niner
April 4, 2012, 06:51 AM
Is the primer flattened and flowing into the pit? If yes it sounds as if you have a pressure problem. If the primer is backing out of the pocket but not flattened you may have loose primer pockets or worse yet a headspace issue. A worn firing pin hole can be bushed. I would not weld on a bolt face/head as you could/would change the heat treatment qualities of said part.

2_Grumpy
April 4, 2012, 07:19 AM
The primers are not pressure flattened, the primer does flow into the pits even with the lowest loads, but not as bad.

Wyosmith
April 4, 2012, 09:41 AM
Yes they can. I have done it several times.

However if the primers are not flowing into the gas cuts to a point they are causing problems you are better to leave it alone.

If you do need to fix the face because the cut is too deep it's a good idea to face the bolt back about .020" and then set the barrel back a turn and re-chamber. When you remove .020" the extractor will still work fine and in most cases facing back .020" will eliminate the pits or at least make them so minor that they are no longer a problem.

In the most extreme cases you may need to bush the entire bolt face and re-machine it to factory specs, but a new bolt is cheaper, so I only do that kind of repair when the gun has some provenance or special value, so that the customer doesn’t want to replace any parts. If you were working on Alvin York’s personal rifle such a repair might be justified, but in 99.9% of these cases you should just get a new (or newer) bolt.

Gunplummer
April 4, 2012, 11:39 AM
Then you need a shorter F/P on some models. You are right about a new bolt being the cheapest way to go.

edward5759
April 4, 2012, 02:04 PM
The last one I did was about $300.00 dollars.
I did the TIG filling, and machining. Then sent it out for heat treating, and re-blueing. came out nice but like others have said it's cheaper to buy a bolt!

brickeyee
April 4, 2012, 03:11 PM
smiths talk about welding the firing pin hole closed and then redrilling it in true dead center, on some accurate rifle actions

Only if they are crazy.

Welding on a bolt near the lugs is a really bad idea.

A bolt with rear locking lugs might be OK (though they are not normally considered great candidates for high accuracy), but not a bolt with front locking lugs.

Even the possibility of altering the heat treat in the bolt and locking lugs is not worth welding near the lugs, and the bolt face is near the lugs on a front locking bolt.

The bolt face is bored and bushed, then a new firing pin hole drilled.
The bushing can be a press fit to eliminate the additional work of threading (and the loss in strength compared to solid metal).

The bushing normally has a larger diameter at the firing pin face, then steps down at the rear.
This allows the flange on the bushing to transfer more of the load to the machined back bolt face.

2_Grumpy
April 5, 2012, 01:07 AM
Thank you to you all.