A little OT but there is an article in the 1979 Gun Digest by Peter Barrett titled "Two Inches of Pleasure & Problems" in which the author details his attempts to take a 5 1/2 lb Holland & Holland sidelock 2" twelve & alter (taking it out of proof) it so he can shoot 1 1/8 oz loads in it (apparently the gun survived intact).
Why anyone would want to shoot 1 1/8 oz loads out of a 5 1/2 lb gun is beyond me not to mention taking a nice H&H 2" sidelock out of proof.
There should be an special place in hell for people that do things like that even though there wasn't as much information available about English guns, "Proof" & proper loads back then.
Nevertheless, an interesting read & lesson on how not to do things & why you need to do a very detailed inspection when buying used guns.
