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Posted: 10/1/2006 7:15:03 PM EDT
| should you get them or not looking at getting a mega upper and need to know what one to get |
+1 M4 cut reciver: use w/ M4 cut bbl std/non-m4 cut: can be used w/ either bbls w/ or w/out M4 cuts |
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I found that after shooting a few hundred HP cartridges that they would start to make their own M4 feedramps. The black finish and anodizing looked worn out. I used a dremel and made my own cuts in the upper receiver and barrel extension. I actually did have some FTFeeds where the bullet tips would jam up in the spot prior to me making the cuts. After the cuts, the AR15s ran fine. I suspect the mag followers (Magpul Gen I) had more to do with it, but I figured that the bullets would wear two notches in the upper receiver anyhow. |
This is usually either incorrect tension on the mag release or a bad magazine. On the magazine it could be a bad follower, a weak mag spring, damaged feed lips or a mag catch hole that has become elongated. |
Yes I agree. I swapped out the MagPul Gen I followers for USGI green followers, and the rifle ran like a bat out of hell. However, under normal conditions, some bullet tips can still wear away at the upper receiver (where M4 feedramp cuts would normally be found). I had some FTFeeds with WWB 45 gr JHP (the ones with tips that looked like honeycombs) in known-to-work mags in known-to-work rifles. |
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