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Posted: 3/19/2014 4:04:10 PM EDT
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I have a RRA upper on a CMMG dedicated lower. With no BCG the halves mate just fine but with it in the rear take down pin won't go in all the way. Switched to other lower, same issue. The BCG is keeping the upper too high for all the holes to align.
Ever seen this? |
| Had the same problem, If actuated the charging handle I could get the halves to mate but then the bolt wouldn't fully go into battery without jamming everything up to the point where I had to use two hands to pull the charging handle back again. Turned out that the RRA bolt was wedging against the bolt hold open and causing all of the issues. I placed colored electrical tape over the bolt to show wear allowing me to see where the interference was occurring. About 5 minutes with a Dremel and polishing wheel http://www.dremel.com/en-us/Accessories/Pages/ProductDetail.aspx?pid=425 and 3/16" of material corrected the issue. I went a little bit at a time until the upper functioned correctly. Good luck |
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Quoted:
Had the same problem, If actuated the charging handle I could get the halves to mate but then the bolt wouldn't fully go into battery without jamming everything up to the point where I had to use two hands to pull the charging handle back again. Turned out that the RRA bolt was wedging against the bolt hold open and causing all of the issues. I placed colored electrical tape over the bolt to show wear allowing me to see where the interference was occurring. About 5 minutes with a Dremel and polishing wheel http://www.dremel.com/en-us/Accessories/Pages/ProductDetail.aspx?pid=425 and 3/16" of material corrected the issue. I went a little bit at a time until the upper functioned correctly. Good luck This is 100% correct. About a year ago I posted pics of the mod that needed to be done to the BHO. If I can find them I'll repost them. You don't need to remove much material to make it work properly. Go slow and test-fit frequently to see when you've got just enough clearance. |
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