If you can get it to work, the 220gr. Hornady FN (small FN) is a VERY accurate bullet that works perfectly from 1,900fps up to 2,200fps. Above that speed, I do not know.

I was only pushing them at 1,940fps (42gr. H335) from a .375 Winchester M94 - 1st both shoulders (blade and blade) and under the hide far side. The second moose, bullet hit 3rd rib up, angled through the right lung, through the shoulder blade and under the hide off side.

Beautiful penetration and both bullets were perfectly expanded. Both moose were 90 to 110yards distance.

Barnes still sells the Old Style 255gr. in both .375" and 378" as well, IIRC.