Only if you use bullets that are very fragile. A factory loaded 300 Win mag cartridge isn't really all that fast of a cartridge.

A .270 Winchester (considered by many to be the perfect deer cartridge) launches its bullets just as fast as a 300 Win mag. The differance is that the 300's bullets are more heavily constructed and will expand at a slightly slower rate than a .270 bullet.

Basically the heavier and larger the bullet the less 'explosive' it becomes and the less meat damage it will do, assuming the same bullet design and same velocity.