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Posted: 6/27/2005 7:49:10 AM EDT
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Do the current Rock River Arms Upper receivers have the M4 cuts? I saw one a recent gunshow and it did not. I'd like to get an RRA upper, but I need the M4 cuts. Any help would be appreciated. |
| Rock River M4 cuts are done after the fact, with a Dremel. They come out irregular looking and cut into the anodizing of the receiver. Since they are not needed for semi-auto operation, I wouldn't have them unless both the receiver and barrel were desinged for them. YMMV. |
| are you talking about the feed ramp.......or the barrel profile? if it's the feed ramps........you really don't need them, mine RRA doesn't have them and it feeds great. I don't believe that they are needed even if was full auto......the M16A1 and A2 never had them, and they function without a problem in auto fire......I believe it's nothing more then a colt ploy to patent the "cuts" that aren't necessary. |
They are an enhancement that would allow more reliable operation with full auto AND questionable/worn magazines. If you don't have either or both, the M4 feed ramps will do nothing for you. If you have feeding problems with a rifle that doesn't have M4 ramps, something is wrong/out of spec and that particular problem should be fixed. One of the few possible exceptions would be that it allows the feeding of round nosed rounds better, but even these should feed fine in a non-M4 rifle, with everything in spec. |
With an in spec mag and an in spec lower receiver, this should never happen. The bullet tip hits somewhere near the middle of the ramp on a standard barrel extension. The ramps are insurance against misfeeds like you describe, but they should never happen anyway. I have rifles with and without M4 extensions and shoot the same gammet of ammo out of all of them without issue. YMMV. |
| I fired over 50,000 rounds in the last ten years and I have never had the enhanced feed gizmos. 7 colt ar's with 14 different uppers and not one single jam or stoppage. Of course I only used really good condition GI magazines(colt,center,etc). Once fired 3000 rounds in one day with a preban 6551 colt and it didn't stop. maybe its better for me to never have them. I bet if I got an upper/barrel combo with them it would jam. It works for me and I'm not fixing it! Oh. yeah, I also don't have those green followers with my mags. And I also fired many thousands of my own handloads. |
And if I drop my mag or flop down on my chest and damagage the feed lips just microscopically or my spring wears out at JUST the wrong time I cant say "Time out this should not happen if my stuff was 100% to ideal spec" either. I know the failure happens, I dont want to chance it happening at the wrong time. This is the same reason to use cannelured bullets, anti tilt followers, M16 carriers, chrome lined chambers, forged recievers and FSB, etc on all my rifles. Sure a pristine weapon will never NEED any of those items under ideal circumstances but why should I not use something I know will eliminate the admittedly rare failures that are KNOWN to occur in the AR15/M16 family of weapons? The bullet tip jammed at the base of the feed ramp is a known type of failure. |
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i have never had any issues that needed the m4 feedramp. but i did purchase a cmt upper with the feedramps cause they are machined in before anodizing and the recon bbl had it too. both match nicely. just got it cause it was no extra cost to me and a little added insurance. |
Was this a recent change at CMT? I inquired about the feedramp cuts several months ago, and CMT stated that the cuts were made after anodizing. |
I recently got a CMT upper receiver from G&R Tactical with the M4 extended ramps in it and they were anodized. |
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