I know RRA isn’t known for making really nice M4 feed ramp cut on their rifles (upper receiver). Here’s what I have. I’m shooting semi only…at most rapid fire (if I have to). Do these look like a potential weak point to you guys? They aren’t machined really deep. I’m trying to right the wrongs so to speak if there are any on my Entry Tactical.
Looks like they did a little Dremel work on an standard receiver that didn’t have M4 feed ramps machined into it. I wonder if the barrel ext. is regular vs. M4? It should be good enough, but I don’t think it has a genuine M4 receiver/receiver ext. feed ramps. Looks like what I did to a Stag upper I once had.
I always wondered why RRA bothered to dremel the feedramps.
I mean the M4 upper is only few $$ more than non M4 and the time with the dremel is not free. 
I guess the only true way to tell is to put rounds through it. But generally speaking, do I have something that is bad?
I don’t think you’ll have any problems, as long as you use good mags and shoot 55-62 gr. FMJ ammo IMHO.
FMJs and especially a crapload of soft points because that’s what we are allowed to carry in our work carbines. No FMJs are allowed.
Knowledge base threads: http://m4carbine.net/showthread.php?t=193
I would try some 69-75gr ammo and see what you get. If the gun runs, then you are GTG>
From looking at the pic, they look like a hack job and would not accept them.
C4
Just curious did you do that Dremel job yourself? Just curious because in pic #3 there appears to be shavings on the right side of the inner part of the receiver.
Hell no. It’s lint/dust from my floor and the light. The rifle is 100% unfired by me. I haven’t had the chance to buy mass quantities of ammo and hit the range.
Wow, if that appears to be metal shavings to you, I wonder what else you see. 
I’ve put about 500-1000 rounds downrange with my RRA, on feed ramps that look exactly the same with absolutely NO hiccup. (Actually I’m glad that you posted this because I’ve always been curious about the feedramps myself.)
While they’re not M4 feedramps (they don’t look like it, right?), I’ve shot about 100 rounds of 50gr hollowpoints out of it and never once did it fail to feed, fire and extract.
In my humble and relatively inexperienced opinion, unless you’re shooting full auto in adverse conditions I wouldn’t worry much about the feed ramps.
Hope this helps.
Edit: I have to admit, these LMT feedramps are sexy (and confidence inspiring) though:
Good to hear about your RRA. Yep, those LMT ramps look sexy as hell. Time to find ammo. sigh
While they’re not M4 feedramps (they don’t look like it, right?), I’ve shot about 100 rounds of 50gr hollowpoints out of it and never once did it fail to feed, fire and extract.
That round count & grain weight doesn’t test M4 feed ramps (fyi).
In my humble and relatively inexperienced opinion, unless you’re shooting full auto in adverse conditions I wouldn’t worry much about the feed ramps.
This incorrect. M4 feed ramps help on SA, especially with ammo that is above 62gr.
C4
Sometimes I see dead people. Depends on how much I have had to drink.