For longer range shooting than 200 yards and using an Enfield, the .312 Express is a worthwhile re-chamber. Mine was done on a #4, same action as a #5. This action allows somewhat heavier loads than can be delivered from a #3.
: My version of the .312 Express easily does 2,960fps with 180gr. bullets and the standard box magazine handles 5 rounds without modification.
: Some #4's and 5's shoot 220gr. .308 RN's very well.
: The .312 Express is a necked down .350 Rem mag.
: A friend of mine has used the #3's for 40 years on deer, bear and moose - mostly with the 215gr. RN or 220gr. .308".
: His results and faith in the round speak well for it. I am curretnly re-barreling a P-14 for him, with a .308 barrel, but chambered with a standard neck so it will take .303 factory ammo. He thinks highly enough of the round, that he is putting a new barrel on one rifle, with fctory chambering. As I said, that speaks well for the round.