Hi all - need some help here.

I was out firing my Aydt rifle this past week. I was trying out some new loads using Remington 2 1/2 large pistol primers. While I've read that the pistol primers can improve ignition with lighter striking rifles, I've also read cautions about using pistol primers because they seat lower in the pocket and have a tendency to cause an imprint/crater on the block face. I thought I'd be okay because I picked some brass that had a shallower pocket depth and I also added some paper in between the primer and pocket to try and get the primer to seat more flush on the case bottom. 

Well after my session (about 40 shots) while cleaning the rifle I notice an imprint on my block face.    I guess my precautions weren't enough. The pitting and scoring on the face was already there but the circular imprint is certainly new. 

So any suggestions to what I might do to rectify this? Would switching back to large rifle primers be all that's needed, or now that the imprint is there will it just keep getting deeper. Would it be okay to lightly grind the block face (a few thousands with in the safe head-space range) to try and make the face more flat again? I'd hate to do any work on an original shuetzen rifle. Besides that would just finding a replacement block for shooting be the way and keep the original and not fire with it any more? Any suggestions / thoughts would be appreciated. 

-Dave

Thanks ssdave

Just for the record - I've put a couple hundred shots through this rifle using Fed 210 large rifle primers without seeing any detriment. I only saw this after firing about 40 Rem 2 1/2 large pistol primers. I'll switch back to the Fed 210 (with what few I have) and see if it gets worse.

That gas cutting that you said was there- I presume from
when you were using the rifle primers?
That ring of gas cutting is from leakage Around primers that have not fully sealed in the primer pocket.
I had such gas cutting in the bolt face in competitive shooting with an AR. Happened with some Russian ammo supplied briefly to the team. 
Lucky, bolt heads are relatively cheap and available
Now, the depression which occurred while shooting 40 rds with LP primers.  Can I presume that the original Aydt block is relatively soft?   
I would definitely suggest you have the block bushed with a
modern hard steel insert as ssdave suggested, too.
beltfed/arnie

There are two ways to repair the block face. One involves milling a hole in the face large enough for a plug or bushing, and the hole and bushing are usually threaded, then Loctited in and milled flush. 
The other way is a dovetail cut across the face of the block, and a filler fitted into the dovetail slot also installed with Loctite. Either works great, and if done right will not hurt the value of your firearm.
if you tell us your location it might help guys point you towards someone close by.

Here is a photo of a Winchester 1885 with a bushed breech block face. There are numerous designs to accomplish the same thing.

I like singleshotsam's method. It certainly would require a lot of experience and skill, but it would be far and away the best solution.

Contact singleshotsam, you won't be sorry.

Not to get controversial but several Schuetzen books advise using the large pistol primers because they have softer/thinner cups more in line with what the old black powder primers had. My rifle is a light striker so has harder time with the large rifle primers. I can point to several books that call out Rem 2 1/2 pistol primers in 32-40 cartridges. The brass I used actually had pocket depths on the shallow end of the large rifle range and the Rem 2 1/2 primers are on the high end of the pistol primer end. So all in all the bullets were not seated more than a few thou under flush. I’m thinking the smaller diameter boxer primer to the original Berdan primers used with this rifle probably puts more pressure on the breach face too. Albeit good point that  metal shim probably help but I’m not away where I could procure such shims, any advise there?