Guy's I have an Olyarms' K3B and would like to use a CMMG upper to make it a flattop.
My ? is if the Olyarms' part's would go together well with the CMMG upper?
I don't wanna drop $$$$ on an upper and not have it work properly.
I'm a year in on the AR, so still learning about them.
gotta admit since getting this one I have taking a liking to the lil "bugger"!
I don't know what model the K3B is, but I do have 3 oly/stg guns. I've swapped out two of the uppers I had for flat tops. It takes about a half hour including the 15 minutes to find all the tools. I didn't have any problems swaping the A2 for the flat top. All of the manufacturers have some combinations of uppers and lowers that fit tight or loose and thats about the only thing you'll run into. The gun with the most slop in the upper to lower fit that I've had was a DMPS. The olympics I have seem to be on the tighter side.
Gunco Good ole boy
Unless something has changed recently, the only ones that are different are the older Colts. Adapters are available though. If you have a little slop, an Accuwedge will take care of it.
Nope, nothings changed. There's just a lot of people out there that'll bash any non-pony ar15s. Olympic used to have a budget ($499) ar15 with a cast upper and lower and some developed cracks/broke. There was a picture floating around a while back where one of the uppers failed just behind the barrel nut threads. And thus a lot of people bash all of their guns even the forged ones and say nothing's in spec and they won't interchange. I haven't had that problem though.
Originally Posted by tanvil