I started out with a Bushmaster 223/.556 but quickly realized not enough fire power. Then I built 7.62x39 after working out FTE turned out to be a great gun. It now shoots brass or steel cased equally well. Then I bought a 450 Bushmaster to go bear hunting in Alaska. Great fire power, loads of fun to shoot and very accurate for such a load. Just bought a DPMS Compact hunter in 308/7.62. Picked up a few Magpul 10 round mags and love this gun. This is now my long range AR, as well as my new deer rifle. But as for nock down power under 200 yards the 450 is hard to beat.