While doing more research on bullets available in .375", I was very suprised to find Speer listing their 270gr. Spitzer BTSP as a varimint bullet.

The URL below takes you to the Speer page that catalogs this bullet as varmint use. I suspect this classification is base on the bullet contstruction being conventional as in the core is not soldered to the jacket as in bonded or hot-core construction. If this bullet is loaded to high velocity it may act like a varmint bullet even though it weighs 270grs. This may limit penetration on biger game like Elk on a quartering shot.
If this bullet was loaded to a lower than max velocity it would probably hold together and just mushroom in the classic fashion with less core and jacket separation.

http://www.speer-bullets.com/default.asp?s1=7&s2=27