Home Forums Hunting & Shooting Gunsmithing Question about Rem 722 bolt face (interesting observation) ???

After examining lots of my spent brass ( all fired from this same rifle) it appears that most all of the primers have this hairline circular crack around the rim of the firing pin divit. Could there be something about the firing pin that is causing this, or is it the fact that the primer is unsupported in this region that causes the crack?

Yes it is. When you have excess clearance between the f.p. tip and the f.p. hole, the primer cup material 'flows' into that area during firing. The primer cup thins as the metal is displaced into the area between the pin tip and the hole, the primer cup cracks because the material is now thinned, and the primer either 'blanks' (is pierced) or as in your case...simply leaks high pressure gas against the bolt face. Your bolt is the perfect example of this. The first thing most people will throw out there is that it's from "...excessive pressure", when in fact that may not be the case. Excessive pressure compounds the problem of course, but isn't the sole cause.

When you have the clearance between the pin and the hole optimized, all of this goes away. The best way to do this is to have the bolt face machined by an accuracy 'smith that has the process down. I can't emphasis this enough.

Stan Ware @ SGR has done several for me and as always, his work was flawless. I suggested Gre-Tan because Greg has a dedicated lathe set up to only do these modifications and his turn around time is very, very short.

The problem is obvious. The solution is quick and relatively inexspensive. Not much more to say......

Good shootin'. -Al

are you using pistol primers and hot loads?

This explanation corresponds most with what I'm finding with the bolt face and spent brass. Mainly because some of the primers are hit off center and some are not. This tells me there "has" to be some slop between the firing pin and the firing pin hole. Also, since I purchase the rifle used, I cannot be certain what ammo was used, however, I have owned the rifle for 20 years and have never used anything but factory ammo. Some of the ammo could be called "vintage" but factory none the less.

Is your barrel fouled with copper?

As a matter of fact, I have been trying (with no success) to get this barrel clean. It is fouled with something that I have been unable to remove. I must admit that I have neglected this barrel and not taken care of it like I should have. Does copper fowling have any significance here? thanks

Still wanting to hear more about the copper fowling and how it relates. thanks

Copper fouling can significantly increase the pressure in your chamber, thereby causing primer leakage and bolt face erosion. Not only that, your accuracy can go to hell. Pick up a bottle of Sweets 7.62 Copper Solvent and just follow the directions on the bottle. A nice polish with JB Bore Shine can help keep the copper fouling under control. I prefer Shooter's Choice Bore Solvent for regular cleaning, as it tends to remove trace copper before it can accumulate.

+1.excellent work