Making a punch and die would simplify the making of brass/aluminum/?? washers...well......once the die is made it would be simple.

Guy's I have over the years heard of this concern a few times. Early on a I spoke to friend about it and he agreed it might happen. His response was I now seat my Pistol Primers in a Large Primer pocket FLUSH so there is no running start for the Primer to beat up the breech block face. I left it off at that and have never concerned myself. Regards, FITZ. OLD TUCK

My main CPA has been in use since 1994, brief use lgRifle Mag primers then to Large Pistol probably 10,000 CF shots no issues with the breech block, well over 10,000 RF.  Switching barrels and block one reason I like Lg Pistol. Run the same Hammer spring tension CF RF and the lighter RF Hammer setting makes the gun easier to cock.

Boats

For what it is worth I have never heard of peening of the breech block using smokless powders.  I believe it is when using full power loads of black powder that causes the problem.  Black is a low grade explosive and creates instant pressure compared to smokless.  The primer gets blown back with more velocity than with smokless.  I am not an engineer but that is my theory for what it is worth.  I fixed my rifle and shot rifle primers and did not have anymore problems.  And I only had .002 head space when I built the rifle and it did not increase with use.  Now with my 32-40 using paper under the pistol primer the primer is flush with the rear of the case.
I will continue to use pistol primers without the paper when using smokeless powder with no fear of peening the breachblock.

one might want to consider, and I suspect someone on here already has,  researched the primers to start with.  Some primers are hotter than others.  It may be worth trying the brand that is the "least" hot.  If printed material is not available, and I know it is on shotshell primers, a good chronograph would be a big help .

There was much discussion of the “peened breechblock syndrome” on the Shiloh Sharps site; probably ten years or more back.  IIRC, most of it was in connection with the general inferiority of Italian copies of black powder rifles vs. the American versions.

When it became obvious that the better Italian copies had none of the poorly-hardened parts that allegedly peened themselves into uselessness in a few shots, the defenders of American infant industries switched gears from metallurgical expertise to international currency expertise, claiming that an American replica could be gotten for the price of a couple Happy Meals more than an Italian one, given the fluctuation of the Euro vs. the Dollar on the Swiss Bourse, dont’cha know.  With about the same nodding acquaintance with the truth as the other accusation.

Certainly a poorly-hardened breechblock will show peening, no matter who makes it, but I have seen none of this phenomenon in either my US or Italian blackpowder rifles, and I use Federal GMM Large Pistol primers, with primer wads punched by the primer on seating.

The idea there is to generate the mildest impulse possible, so the powder column doesn’t break up and the bullet doesn’t move appreciably before the powder charge itself starts to burn.  It seems to work, for me at least; I get better targets with the wads than without them.  It might well be voodoo; I read an article way back when (in Rifle or Handloader, can’t remember which) where the author queried the component manufacturers and found that there is exactly the same weight of priming compound in Rifle and Pistol primers of a given size and type.  The only difference, they said, was the relative hardness of the cups, and, of course the depth difference in the Large versions.

I use strips of paper cut from Official ASSRA targets for the primer wads.  The paper is very uniform, of a good thickness, and, since all the holes are in the exact center,  there’s plenty of paper left to repurpose.