A 7mm 120 Barnes hollow point would be good for deer hunting since it's designed for deer. Most other 120's in 7mm are thin walled varmint bullets and won't hold up to medium/large game. Sure you can kill deer with a light varmint bullet. But sooner or later you'll hit a rib just right, or the shoulder and the bullet will break up on impact and not penetrate.
Yeah, people shoot deer with 100 grain bullets in 243's but remember that bullet is made for medium game.