Haha..... Bgf, you beat me to it!-Ron
Go to www.TCArms.com, Manuals section, View and/or download the manual.Data charts are in the back, Max listed for a .54cal is 120grns Goex 2F.Not sure why you'd need to 'proof' it, or what you'd look for, they are mass produced barrels with a history for excellent quality...