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9/17/2020 5:59:48 PM
Posted: 7/4/2012 11:12:49 AM EDT
Hey everybody.  I recently installed a new 20 inch FN barrel on a new Cmmg upper. When I took it to the range it would not feed the rounds. The bolt just smashed the tip of the bullet into the space where the barrel sits in the reciever. It seems like the rounds dont angle up enough. I tried different mags and another lower with all the same results. It is just this upper that I have a problem with. Did I put something together wrong?
I appreciate any input.
Link Posted: 7/4/2012 11:38:31 AM EDT
M4 feedramped receiver with a rifle feedramped barrel?

Joe
Link Posted: 7/4/2012 12:31:15 PM EDT


Link Posted: 7/4/2012 9:55:24 PM EDT
Ok. Thanks for that. U guys are right I have an M4 upper with the rifle feed ramps. Guess I need to get another barrel, another upper, and if I do that I might as well get another lower...... Lol
Link Posted: 7/4/2012 11:24:41 PM EDT
Originally Posted By CTOWN5:
Ok. Thanks for that. U guys are right I have an M4 upper with the rifle feed ramps. Guess I need to get another barrel, another upper, and if I do that I might as well get another lower...... Lol


I like the way you think, Sir.  
Link Posted: 7/5/2012 7:59:41 AM EDT
Dremel
Link Posted: 7/5/2012 8:19:57 AM EDT
Originally Posted By Sydwaiz:
Dremel


Put the dremel down and step away slowly...  

You could use a round file or needle file to create m4 feedramps in your extension but I think a wiser decision would be to get an upper receiver without feedramps.
Link Posted: 7/5/2012 9:51:21 AM EDT
Another option, you could send the upper and barrel to ADCO and they'll open up the feed ramps to match that of the receiver... although with much patience and some files you can do the exact same thing they do, but for free.
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