My 80 year old uncle gas a 303 e field and when we tried to shoot it the bolt will not close completely. I'm thinking it has something to do with the ammo. When you chamber a round it will go into the chamber but when you turn the bolt down it will go almost all the way down except for the last 1/4 inch and the bolt won't lock. The ammo was modern 303 British but maybe we need another type 303 ammo.