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1/25/2018 7:38:29 AM
Posted: 11/21/2005 5:25:24 AM EST
haven't received the upper yet, but was wondering if there are any compatibility issues such as the size of the pin-holes on the upper vs. lower (as I have heard is the case between bushmaster and colt)-- any info it greatly appreciated... thanks
will seabrook
Link Posted: 11/21/2005 5:49:44 AM EST
99.9% positive you aren't going to have any problems. I've got a CMT upper mated to a BM lower and no problems whatsoever.
Link Posted: 11/21/2005 5:55:46 AM EST
[Last Edit: 11/21/2005 5:56:11 AM EST by Boom]
Link Posted: 11/21/2005 5:59:21 AM EST
thats good news--- thank you very much

will seabrook
Link Posted: 11/21/2005 6:35:14 AM EST
The pin issue is strictly a COLT problem, as they are the one's who decided to produce rifles utilizing a different pivot pin size for some of their rifles.

Mating issue of these uppers or lowers could require special aftermarket pins designed to hold a standard pin size upper or lower to the oddballed Colts.

This issue is documented very well here at: www.biggerhammer.net, look in the upper section there for pics and pin sizes......

Link Posted: 12/2/2005 11:52:17 AM EST
No problems with my BM lower and CMT upper.
Link Posted: 12/2/2005 12:16:11 PM EST
I have done 4 builds with stripped Bushy lowers and CMT uppers. No problems. Good fit.

Link Posted: 12/2/2005 12:16:20 PM EST
NP here at all either, BM is a little deeper black but thats it.
Link Posted: 12/25/2005 5:58:32 AM EST
You said it is a little deeper black, Is it very noticable?

Link Posted: 12/25/2005 7:13:48 AM EST
[Last Edit: 12/25/2005 7:14:47 AM EST by shamayim]

Originally Posted By blaib:
You said it is a little deeper black, Is it very noticable?


Depends on how ticky you are. If you're a perfection freak, you probably shouldn't be an AR owner in the first place; since factory new complete rifles often show a slight color difference between upper and lower.

On the other hand, if you're like most of us, you'll put a light coat of lube on the two pieces, and not notice any difference except maybe when you're outside in strong sunlight.
Link Posted: 12/25/2005 7:18:38 AM EST
I had a RR lower that was pretty tight with some of my BM uppers,some of them needed a couple of file strokes on some of the internal stuff to fit.
If you don't try to mix colt stuff with anything else (it can be done but is too much hassle in my op) you will likely never run into any problem and almost certainly never anything that can't be simply dealt with.
You do realise that CMT is the actual factory that makes many of the forgeings for the big AR companies?
I am not sure who does the final machine work (drilling holes and cutting slots ect) and who does the finish
of the parts but CMT is supposed to be the origin of lots of goodies .
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