To me and 4-5 or them IIRC Colt is always very very good functionally, it's a carbine gas IIRC, DD has some mid length gas guns, I like them. Noveske is good, uses FN barrels, had RRA and Bushmaster, RRA is just ok, bushmaster blows, never had a spikes but have 3 of their lowers. I have a stag 6.8 bolt it is good, my friend has a stag carbine, no problems. I am saving for another Colt I feel you should always have at least one Colt.
