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Posted: 7/25/2017 4:21:53 PM EDT
| This is my first post to this board. Are all Colt AR15 uppers compatible with all Colt AR15 lowers? If not, why not. Thanks. |
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No. You have some machinegun uppers that are open bolt that will not work on lowers. Early colt civilian uppers had a large hole in the front and it takes an adapter to put a standard upper on one of them. You do have adapters.
Also on some colt lowers they have a auto sear block that prevents a full auto bolt carrier from working with them. You could switch to a semi auto carrier and be fine though. Edit: While not asked some of those older colt lowers had larger fire control pins in them. Means you need special parts to replace the trigger group(or bore out standard ones). |
| Thanks for the info. I bought a Colt 7.62 x 39 upper several years ago, and the barrel was manufactured in the 1990 -- 1995 period. I was thinking of buying a new Colt M4A4 lower, but did not know if there would be a compatibility problem between the upper and lower. |
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Quoted:
Thanks for the info. I bought a Colt 7.62 x 39 upper several years ago, and the barrel was manufactured in the 1990 -- 1995 period. I was thinking of buying a new Colt M4A4 lower, but did not know if there would be a compatibility problem between the upper and lower. |
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