Upper for RRA barrel? M4 feedramps?

AR/M4 AR Technical Discussion
1

I was recently given a 14.5 RRA barrel by a family member. He ran the barrel through a few matches and decided he wanted a stainless bbl. I thought I would throw together a little budget build with it. Here’s the barrel:

http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=272

I have everything I need except the upper receiver and BCG. I am on BCM’s website and they offer M4 feed ramped uppers and non M4 ramped upper receivers. Looking at the barrel, it looks like a cross between regular and M4 feed…

I would like to order the M4 receiver but I don’t want the lip to interfere if the barrel doesn’t match up. Any one have any knowledge as to which receiver to order? If I need to just purchase the standard receiver, then I will. Thanks for the help.

2

maybe this will help

https://www.m4carbine.net/showthread.php?t=193

3

a standard receiver should work with both M4 and rifle feedramps
an M4 cut receiver will only work with M4 feedramps

if you have some homemade WECSOG dremeled feedramps in your barrel, they were probably “matched” to the upper… I would talk to your family member and take a look at the upper to see if that is the case… then i’d find out what barrel he is going to use and trade him a new upper for the one dremeled to “match” your barrel…

4

I am very familiar with that link shittercrew. I studied it while looking at the barrel I have before posting this thread. I don’t know what kind of receivers RRA uses. I am assuming a non M4 feed ramped receiver. Correct? That is my only real question…

5

I sent RRA an email a while back when I was looking at barrels, and they informed me that none of their barrels came with the M4 extensions. They all contained rifle extensions.

6

Thanks Fry, that helps. I will just go with the standard BCM receiver.

7

You could replace the barrel extension if you want, thus getting the feed ramps that you want.

8

I don’t know any bit on how to do that. I assume I would have to send it to AR15barrels or someone to do that work. Is that correct, or could a local gunsmith handle it?

9

There has got to be someone in your area who builds ARs as a hobby and could help you out.

10

It’s possible… I’ll look into it. Thanks for the responses.

11

Finally a clear illustrated picture of what M4 feed ramps are.