What is proofing?
According to the Birmingham Proof House in the UK, proofing is “the firing through the barrel of a considerably heavier load than is customary in the shooting field, thereby setting up pressure and stress on barrel and action much in excess of the pressure generated by standard load...and is intended to, disclose weakness in guns...” But it is more than that. It is certification by a government entity that such testing has been done in accordance with that nation’s recognized standards. Not all nations adhere to the same standards and requirements as regards proofing. There is much variation in the loads required by the varying governing bodies - with most calling for a load of 130-140% of the service charge and a specified quantity of shot for the proofing of smoothbores. Also, not all countries require each individual piece to be proofed. In those countries, manufacturers may select a random sampling of products for proofing. If the samples pass, the entire lot is deemed ‘proofed.’
At present, there are no proof houses in the United States which proof muzzleloaders. There are likewise no recognized proofing standards in the US by which a muzzleloader may be proofed. Thus, for example, it would not be possible for an American manufacturer of muzzleloaders to offer a ‘proofed’ weapon unless that weapon was first exported to a country which has a recognized proof house, the piece was proofed and certified there, and then the weapon was re-imported into the United States.
Test Firing:
Some muzzleloader manufacturers and importers in the US offer what they call a ‘proof,’ but actually it might best be called a ‘Test Firing.’ As mentioned previously, there are no standards, so each maker test fires to his own standard. During our first two years of operation, we test fired each and every weapon we sold. Since then, we have discontinued the practice of test firing each piece as many people do not wish to wait for the time it takes to be done or would rather do it themselves. (It is very labor intensive.)
Below you may view published information on British proofing standards.
- Proof1PDF
- Proof2PDF
- Proof3PDF
Extreme Integrity Test 2010
In 2010, Veteran Arms LLC subjected one of its off-the-shelf musket barrels to an Extreme Integrity Test. The barrel (69 caliber) was removed from the stock, inspected, and then fired with a load of 160% of the maximum recommended charge under controlled conditions. The barrel, of course, was not damaged. In an attempt to achieve structural failure, the powder charge was then increased in increments and the barrel retested. The barrel was fired with loads of 200, 300, 400, 500, 600, and 700 grains of powder and the recommended ball. No damage occurred. Impatient, a load of 10 times the maximum charge was attempted, topped with 2.5 times the maximum recommended weight of shot. (European proof standards call for the firing of shot for smoothbore weapons.) There was so much powder and shot that the ramrod extended out of the barrel by nearly a foot. The result was a very large report, but nothing more. The barrel had no bulges, cracks, or other deformation. Of course, this information is not intended to encourage anyone to exceed the recommended load for any weapon. It is intended only to illustrate what our barrels may be capable of withstanding in order to dispel some misinformation that has circulated on social media.