I agree with Destry, I wouldn't mess with having the gun proofed in England or Europe; and, since I get the impression that you would be experimenting with the proofing process yourself, I would strongly suggest you by-pass that option also. The odds are high that your barrels are fine; however, since you have some doubt, put your mind at ease and have her thoroughly checked by a competent doublegun smith (there may be a problem other than barrels, who knows?). But when you have those barrels checked, be sure to check chamber length; and more importantly, have barrel wall thickness checked/measured as wall thickness will be the primary determinate of barrel safety (a flaw "shade tree" proofing may not reveal; and one, should it exist, could result in serious consequences at some later point). Regards