My brother and I both bought these new SIG SAUER M400 gas impingement carbine rifles at the same time. Very pleased with them...Was suprised to see shortly after purchase American Rifleman(NRA mag.) May 2012 issue an in depth article on them.Some nice updates on this rifle...This is definitely more than an entry level rifle espec.for the price... We shot multiple hollow points along with fmj's thru them rapid fire without a jam....Article said they had a couple instances of a jam on 1st shell entering breach.So naturally we wanted to test this out. Hollow points we used were a some hp hand loads by nephew and Russian Wolf brand non-reloadable 223 hp and fmj. No problems . Nice weapon.Next I think I'm going to look for some see thru scope rings to go with some scope .