Daryl,I've had my fair share of experience with 375 projectiles in my own rifle on buff and scrub cattle.
I recomend two projectiles,both WOODLEIGH'S,
300 grain round nose soft nose.
300 grain round nose solid.
Both have the same point of impact with the same powder load and primer.
Muzzle velocity around 2250 feet per sec.
Always have a couple of solids in the magazine as back up incase things get messy.