Re: 338-378 weatherby
A 250grn bullet would be the lightest i would ever go in a large 338mag. The only way your going to know is try them in your gun. Remember your going after smaller game, light fast bullets will do lots of damage at the ranges your speaking of. Don't be scared of the large bullets, they are made for good accuracy at longer distances. 338-378wby is a large game rifle, with any bullet you choose for deer sized targets there will be issues with bullet expandsion. Go with a good high BC match bullet, the 250MK or 300MK from Sierra, you have a gun that is capable of 1000yd kills, with these bullets your gun is used to its full capacity. I said it in a earlier post, 300MK all the way. Work up one good load and stay with it.