Sorry, I will not send my gun anywhere to attempt a "blowup" as long as I can buy a wall thickness gauge for a hundred bucks. This British proof business is a crock of government busybodyness. When you buy a gun with British proof marks, you have no idea whether the barrels were struck thin after the gun was proofed, even if it was proofed last year. The only thing the marks tell you is the dimensions of the interior, not the exterior or the wall thickness. If anyone has more respect for British proof than I do, let me know.