My 50 yard guns:
Just kidding! I actually do a fair bit of shooting at 50 yards because it's convenient. I run a 50 yard pistol range pretty frequently, and often when there's a break between shooters, I'll shoot one of my rifles for a while. It's even been useful with my .308, just for practice. No, you don't need the best ammo to do some good, worthwhile practice at 50 yards. If possible, use that for doing some unsupported shooting from prone, sitting, kneeling and standing...
Then take that .308 of yours out somewhere and stretch the range, that's a 600+ yard rifle you've got there! Looks good.