English guns were made to digest a specified load, no more weight and strength than necessary was build into the gun. It was a finely tuned precision instrument designed for a specified purpose.
Modern guns are build to take whatever ammo they may encounter - hence the 3" magnum steel shot proof applied to Beretta 687 20-bores: even though most will be used for game shooting with a 2 3/4" 23g or 25g lead loaded shell for game shooting.
I get(unreasonably) distressed when I hear of the butchery of the finest guns that Britain produced by foreign owners who do not understand them and the principles on which they were made.
If a British gun is intended to fire 3" shells, it will have 3" chambers, if intended for 2 3/4" shells, it will have those chambers, if it is made with 2 1/2" chambers- use the right ammo or change the gun for something that is intended to shoot your magnum loads.
