Get 7.62x39 upper for the AR15 and put them in the freezer from now on. I've been using one for years and have taken a lot of deer with it. Hornady SST are my preferred round; but have killed a bunch with plain old Wolf 123HP ammo. Light recoil and deadly on target. Bonus is that the ammo is still very reasonable and you (and kids) can get a lot of practice in before the season starts. C Product mags are also the ones you want for this upper.