The operator I work with built an AR-15 a few months back and, although I hate to admit it, it was the first one I had shot and it is scary accurate at 300.
First mag I put through it was at an 8 inch gong and I hit it 28 out of 30 shots at 300 yards. (I like shooting gongs for fun shooting).
We also shot at several travel size shaving cream bottles with his m&p 15-22 at 200 yards and it was surprisingly accurate. Never stretched a .22 that far before.
But as I said I like the gongs, miscellaneous exploding targets such as tannerite or shaving cream and water bottles, paper, and a buddy of mine works for a place where he can get manicans and hard styrofoam heads.