The Birmingham Gun Barrel Proof House was established in 1813 by an act of British Parliament. And today, the historic testing agency still resides in the same building.
In essence, proof houses test the safety of firearms – particularly the barrels. And they do so in a simple way – firing an over-pressured charge.
The method separates the wheat from the chaff quickly. Properly made barrels and chambers make it through the trial by fire. Those with imperfections split or crack.
Above is a cool video I stumbled upon at Gun Lab, detailing the Birmingham Proof House testing barrels more than 60 years ago. It’s certainly appears to be a much more dramatic method than the copper crusher or piezoelectric systems of today.