Is this right? CMMG 300BLK AR15 barrel

dvdt

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Been discussing changing one of my AR15's over to 300blk with a buddy of mine. He beat me to the punch and picked up a CMMG barrel at Midway.

We were discussing it and he sent me this picture of the feed ramps. Does this look right to you all ? Are you supposed to have to machine the ramps at all for the conversion ?

The upper is a Bushy Predator.

BushyCMMG300blk.jpg


BushyCMMG300blk2.jpg


Mods - if this should be in gunsmith forum pls move. No disrespect intended
smile.gif
Just wasn't sure if this was really considered 'smith work.
 

Redmanss

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Re: Is this right? CMMG 300BLK AR15 barrel

That barrel extension is designed for a receiver with M4 feed ramps cut into it. If shot as is, you are likely to have feeding problems with the 300BLK.

You can have the M4 ramps cut into it, you can get a new receiver (my suggestion), or you can try your skills with a Dremel.
 

country888

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Re: Is this right? CMMG 300BLK AR15 barrel

The barrel has the feed ramps, but your upper receiver does not. I have a couple of AR's like this. I haven't had any problems with them feeding. If you run into a feeding problem you can take it to a good smith to take care of it for you, or if your good with a dremel tool you can do it your self. But I would just shoot it and see. My 300 blackout barrel has M4 ramps but my upper receiver does not. No problems! Good luck and enjoy, its a fun round to shoot

Stephen
 

BravoSector1

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  • Oct 26, 2011
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    Re: Is this right? CMMG 300BLK AR15 barrel

    With the larger diameter bullet...you may not have any issues. If it functioned well before firing 5.56/.223...I would give it a try first and see if it hangs up.

    Dremel option "very lightly, slow go, check often" is probably the easiest fix if you do run into feed issues.