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4/9/2010 7:57:36 AM EDT
My dad has a full auto colt lower and I was was wondering if my BCM upper would be ok to put on it and shoot full auto?
4/9/2010 8:13:53 AM EDT
[#1]
Probably yes.  You'll have to check for the sear relief cut, or have such a cut added if it's not present, to use with a GI sear-type registered receiver.  The AR-15 area at biggerhammer.net has comparison pics of what to look for if you're not familiar with what the sear cut looks like.

If the lower uses a DIAS, then the answer is yes - DIAS does not require the sear relief cut.
4/9/2010 9:23:55 AM EDT
[#2]



i don't think anyone even makes uppers without the cut anymore.



4/9/2010 9:31:21 AM EDT
[#3]
Quoted:
i don't think anyone even makes uppers without the cut anymore.


There's actually quite a few, especially the thick, specialty receivers like DPMS Lo-Pro and other "funny lookin'" spacegun and varmint type uppers.
4/9/2010 9:54:56 AM EDT
[#4]
Quoted:
Quoted:
i don't think anyone even makes uppers without the cut anymore.


There's actually quite a few, especially the thick, specialty receivers like DPMS Lo-Pro and other "funny lookin'" spacegun and varmint type uppers.


good point. i wasn't even thinking of non-standard stuff. those DPMS recievers are just extrusions IIRC, which is why they have no features on them. cost-cutting.

the OP's BCM upper will have the relief cut though.


4/9/2010 10:57:32 AM EDT
[#5]
The BCM should be fine, as long as you have a F/A carrier.
4/9/2010 11:18:57 AM EDT
[#6]
If it has the original BCM bolt carrier assembly, then yes, it should run like a top. Have fun!
4/12/2010 8:40:06 AM EDT
[#7]
yes, it is the BCM completed upper with BCM BCG and Mod 4 charging handle.  Thanks
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