I'd say as long as you stay within the distance that you can get your shots into a circle of about 8" or so you'd be fine. You can get soft point hunting loads for the .303, so you should be OK there. I think I'd use the #4 instead of the #1 simply because of the sights, but that's just me. I've heard of this done before, in fact I recall an article about roughly this subject where the guy went and got a #1 and a load of ammo for it because he came to the conclusion, after seeing a guy with a #1 get himself a nice elk while he himself had a fancy Dakota Arms rifle and got nothing, that if he got one and practiced a lot with it that once he got good with that cruddy trigger his marksmanship basics would be well honed, and help him be better with a good rifle. Hard to argue with that logic, since for less than a decent rifle you could get the Enfield and a bunch of ammo, at that time. .303 surplus is harder to find now, but the basic premise is sound.