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Posted: 2/21/2008 5:16:46 PM EDT
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I took my Bushmaster AR out for the first time about a week ago. I had some problems with feeding rounds into the chamber. I was shooting the 50 Grain Hollow point Federal Bulk Pack. I need to know what I need to do to find out what is causing my problems. Here is how the shooting went. I loaded the factory magazine with 1 round, inserted it into the gun pulled the charging handle back and let go the round fed into the chamber with no problem. I shot the round and the bolt locked open. I loaded a USGI magazine with 1 round and did the same test. Loaded, shot, bolt locked back no problems. I loaded the Bushmaster magazine with 5 shots. Pulled that charging handle and let go, the tip of the bullet caught on the feed ramp and did not enter the chamber. I pulled and released the charging handle again. The round feed properly. I shot 3 of the 5 rounds in the clip and on the 4th round the round did not feed properly and the bullet was pushed back into the casing. I cleared the round from the gun loaded the 5th round with no problem. It being the last round the bolt locked back. I loaded the USGI mag that I had with 10 rounds. I had some problem loading the first round; it caught on the feed ramp again. I pulled the charging handle back and let go, the bullet was pushed back into the casing. I dropped the mag and cleared the round. Slapped the mag back in and loaded and shot the remaining 9 with no problems. Now I am getting frustrated. So I load a 2nd USGI Magazine with 20 rounds. I inserted the mag and released the bolt the first round fed. I shot 5 then it would not feed the next round. I noticed that if I pushed on the back of the magazine I would have no problems with the feeding of rounds. I finished the rest of the 20 rounds with no other problems. I tried a total of 5 magazines in it, the factory Bushmaster and 4 USGI magazines. I have had hit and miss problems. In the 140 rounds that I tried to load 5 of them the bullets were pushed back into the casing. I got it out last night and checked the feed ramps there are no burs or nothing that catches my fingers on them. The feed ramps were not the smoothest thing that I have felt. They had a slight texture to them; nothing that looked like it should catch the tip of the bullet. I looked at how the magazines set in the lower with the upper off. They all have a little play in them but nothing major. This is what I can come up with that could be causing the problem. 1. The Hollow point bullets are catching on the feed ramps. 2. The feed ramps are to rough even though I can’t feel any burs on them and need to be smoothed out. 3. My magazine catch is out of spec and I should tighten/replace the mag catch. It could be a possibility that I got 5 bad mags but I don’t think that I did. I am going to try and go out on Sunday and shoot some Remington UMC out of it to see if the problem clears up. Any help would be appreciated in troubleshooting my problem. Thanks MAHA |
No, Just the Hollow Points. MAHA |
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Short version, Either shoot 55/62gr full metal jacket pointed ammo, of if you just must run HP's, then you will need to have the upper and barrel extension M-4 ramped. The extended ramps allow the use of HP ammo with the worries of the bullet tip catching on the normal barrel extension ramp starting point (read low feed). If you just must shot the ammo in the rifle and do not wish to have the ramps M-4'd, then stick a bent piece of a match book cover between the back of the mag and the mag well. This will cant the front of the mag more upwards, and prevent the low feeds ( bullet tip striking the upper receiver below the standard barrel ramp, causing the set back/jam). |
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I went to the range over the weekend and had the same problem. Was shooting hollowpoint ammo and the bullet was being pushed back into the caseing. It only happened with one of my 4 mags though. I took the rounds from that mag and put them into another and it fed fine. I put that mag in time out and will probably not use it again. It is a BM 30 round factory mag. The other 3 (also BM) fed perfectly. MTC M |
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