So a 200% powder charge. Dont know if Id ever subject my 200 year old muzzle loader to that standard. Id rather hang it over the fireplace. I did shoot it a couple dozen times without incident this weekend. But I dont see the value of proof in this case. I did a 50% overload test, but not to this level.
Proof Laws to protect a buyer are fine and great for the seller, when a gun passes. Gives them a bit of legal cover and the seller knows his new gun has a decent level of safety in use. But I remember a 20 gauge Clark hammer gun which passed reproof and failed within a box of shells. But Im sure a gun which fails, even when not a catastrophic failure, saddens everybody. Old guns deserve to be shot, if they are safe.