Ah, so the failure of a hammer tip/firing pin was to blame for the pierced primer. Now some facts come out. Can you prove the chipped firing pin that caused the issue was due to the conversion? There are a lot of variables there that could be easily argued, that don’t put liability upon the converter. Could have been metal fatigue/defect, improper heat treat from CZ, etc. You can sue anyone for just about anything, winning a judgement is another matter. But there’s a ton of speculation on both sides, not facts as you state. Yes, the ATF would consider you the manufacturer. Putting a muzzle brake on a Rem 700 would also make you its manufacturer. Are you going to be sued in the event of any mishaps? That’s grasping.

Interestingly enough the only pierced primer I’ve seen was due to the exact same reason, it was on a legit double rifle, and said double rifle was made with disc strikers that were not vented.

I’ve got other numerous modern and vintage double rifles in the shop, many without venting. Some by manufacturers with large production and actual mechanical engineers on payroll.

It’s a great safety feature, and I’m putting venting in my double rifles I’m currently building from scratch. I’d question the actual effects they would serve in an actual pierced primer event. Did the venting alone save the day or was it that the firing pin was pushed back, thus sealing gases from entering the head of the stock until the majority of the pressure escaped the barrels from the muzzles. Obviously some gases would escape through that massive .050” hole...