I currently have a Bushmaster A2, but plan to switch to a flattop for more optics choices.  I can't find many places that retail BM parts or receivers, and buying a flattop directly from BM runs about $180.  There are great deals on RRA and CMT receivers, but I've read some negative opinions about fit/reliability of weapons built from multiple manufacturers.  Would I have these issues combining different makes.  How is the fit/finish with BM and other manufacturers? Thanks

Its more trouble than its worth, just get a new completed upper.

Edited for spelling

Its more trouble than its worth, just get a new completed upper.

Not only is buying an entire new upper not an option right now ($), it's not that much trouble to swap receivers.  Plus, BM will do it for free if I buy directly from them.

Its an easy swap, buy a RRA or a CMT (without the M4 feedramp cuts) and be done with it.  You aren't going to have any problems, and its a simple job.

I went through the same phase last year.  I bought a RRA A3 upper direct off their website (you can find better prices from some other places), and had a friend swap my barrel (BM M4 profile) onto it.  There's a really minor color variation between the RRA and BM, but I can barely notice it.

I have a Bushy A2 and I am going to do the exact samething within the next few days.  I have been meaning to do it for a while but just have not gotten around to it.  I also don't want to spend the money for a Bushy A3.  I am not one who babies my AR or worries if it looks "cool" but one thing that drives me crazy is when the upper and lower are 2 different colors.  So I have done a lot of research on who has the closest match to Bushy's lowers.  It seems like White Oak is probably the best match along with CMT.  I still haven't decided if I am getting the White Oak or the CMT but I am leaning towards thr CMT.

Good luck

My CMT A3 Upper matches my BM Lower exactly.
14.5" BM 1/9 NATO w/Perm. Phantom 5C1




Denny has them for $95 shipped in the EE for the Non-M4 Feedramp Cut CMT A3 Complete Upper Receiver.

HS1

Thanks to all who replied.  I feel alot more confident about going with a CMT/RRA upper, plus I'll save a little $$.  Highstrung, nice looking weapon.

Over the last two years I converted all of my A1 and A2 uppers to flattops.  I bought a few of the "blemished" uppers from LAR, I have one now, and a deputy friend has the other on his AR-15.

The other flattops I purchased from J&T.  They were $115 which included fwd asst and dust cover, installed.

They will fit and match your Bushmaster lower... unless your lower is the famous "Bushmaster Purple".