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Posted: 4/10/2004 7:24:57 AM EDT
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I've completed my new RRA Lower using my Model 1 Kit, M4, Post Ban. I'm attempting to connect the two. The "pivot lug" on the front of the upper and the "takedown lug" on the rear are both "rubbing" against the lower. Is this common on RRA/Model 1 Matchups? Is it harmful to grind down the lugs? I've built 7 or 8 in the last 4 years and have never had this problem. Any help is appreciated. |
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Tight is good IMO, as the RRA lower "shallow" rear shelf is known by most (precluding the use of the accuwedge device) are you certain that the rear lug, (while tight) isn't contacting the "raised" rear shelf on the RRA lower? Perhaps ya just need to take a bit of the bottom of the rear lug off. Sounds as if the rear lug "is tight" BUT does go it, which is why I point this out. Measure the distance from the top of the lower (the mating edge) to the rear shelf then compare this distance to the length of the rear lug to determine whether the "shallow" rear RRA shelf is causing your problem. Alot of uppers are tight when mating to lowers, (as stated NOT a bad thing), and taking a bit of material off the lugs while not unheard of best be done in the correct spot, so try the dimensioning out before breaking out the Dremel tool, to make sure your taking it off where it's really needed. Hope this helps, Mike |
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Thanks, Mike. Gives me a place to start. I'd always heard that RRA's were very "tight." I agree, over time, that it's probably a good thing. I do have about 2K rounds of Lake City 5.56 that I'm dying to burn up, so I'm sure it'll get some wear. I'll try your suggestions. Again, Thanks, Jeff |
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OK, whew, problem solved. It wasn't a "shelf" issue but a fitment issued w/ rear lug edges rubbing "well" or rear of lower. I took a fine toothed file, about ten strokes on each rear edge of lug, and great fit. Can't wait to get to the range today. Thanks, Mike, Jeff |
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