That's a good idea Bindi. You could simulate something like it by putting a bayonet onto a No4, put a cork or plastic ferrule over the bayonet and put a Bren bipod over the ferrule. Then range test it and see how it affects the accuracy. That accuracy v the standard accuracy. Your results might close this clap-trap forever

Armourers certainly wouldn't need or use something like it because in the workshop we use a bench vice and 'horse' and outside we use a sandbag supported wrist or at Base workshop, the old Enfield layer.