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Posted: 3/12/2006 11:45:04 AM EDT
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First of all let me say: "Damn I miss Tweak". Normally I would bring this question to him and he would come over and look at my rifle in person. That being said, now I have to try and convey my issue with text. Mega Upper with Sabre Defense 16" M4gery Barrel. Mega lower with RRA LPK. LMT Bolt Carrier and bolt. Rifle worked great for the first 6 months I had it. Ran into an issue with the carrier not being staked correctly and had that fixed (See the pics of my carrier in Tweak's Thread about that topic.). ANYWAY, almost all of a sudden I am having issues with rounds feeding up the ramps in into the chamber. To the point that I've had the bullet actually pushed into the casing. This is more pronounced with the cheapie hollow point stuff, but I've had it happen with 855 as well. It's as if the mag isn't sitting high enough in the mag well. I've adjusted the catch in both directions to no success. The only thing that helps is if I fire while pressing UP on the Mag itself. Any hints? I'm starting to wonder if the Mag catch needs to be replaced or that the lower itself is out of spec. Anyone experience this? Thanks, -PCR |
That was my initial assumption, but no matter what mag, all have issues. I even tried a brand new HK mag, no luck. All of my mags just had new followers (magpul) put in, the springs are all good. Tried an older mag that still had a green follower in it, no luck, factory Bushmaster mag...no luck. Tried one of my mags in someone else's rifle with the suspect ammo. Ran great, no FTF. 
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1. The mag catch may be looser than it was, and allowing the mag to tilt more in the mag well. As pointed out, try tightening the catch. 2.The mag well may be more worn that it was, and this is allowing the mag to tilt more as the rifle is being fired. Tightening the mag catch may help with this one. 3. The mag catch it's self may have worn, and this is allowing the mag to sag down/seat lower in the well more than before. Might want to try another mag catch. 4. If the rifle on the verge of short stroking, the buffer impacting off the back of the receiver may be less than is was before, and this less of impact/jolt is missing to allow the mag to recover (get the top round all the way back up to the feed lips as the bolt strips the round. Since I tend to be a buffer whore (read I run about every buffer thrown my way), my solution is to spring cant tweak all of my mags springs to make sure even if I don't get a strong impact of the buffer off the back of the receiver extension, the mag is going to get the top round up against the lips/ in the right angle as soon as the carrier clears the top round on the way back. 5. Using secret magic, there is a mag on the market the will allow even the funkiest round tip to be feed cleanly into the feed lips (read even the most unforgiving HP tips). If you have been following some of the threads over the last few years, you will remember that this is one mag that has had problems with the feed lips rubbing on the bottom of a great deal of receivers in the AR rifles since it is the highest ridding mag known. The trick will be trying to get your hands on the SA80 mags since the supply has seemed to dry up. |
Cool info, I'll answer each in turn in order to help nail this down.
To add to the confusion, my brother built his rifle the same time as I did, with identical parts and is having the same issues. Thanks for the input guys. |
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Well, I happened across annother rifle yesterday, an OLY (Aint the EE Great?). and checked the fit of A mag and it was very snug, no forward backward wobble. Put the same mag into the MEGA lower and it had considerable movement. So, I swapped the Mag catches to see if that made a difference. NO Is it possible for a lower to be that much out of spec? Or is it acceptable and I need to look at something else on the rifle? Thanks again, Mac |
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On a standard lower, an empty mag should drop free when the mag button is press. On the same token, the mag should not swing in the well like a screen door with a broken latch in high winds. Get Mega on the phone and discuss with them the problem at hand, and if they have a reason/resolution for the state of the mag well. |
According to my vendor, turns out that Mega had a run of lowers that had magwells that were too tight and they may have over corrected. Sending the serials to him tonight, we'll see what Mega does about it. Thanks again guys -Mac |
Well, I replaced the lower (no charge from the vendor) and ran 100 rounds without a jam.  The mag DEFINATELY fits better
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Well I was very impressed with the service provided by Iblis (a dealer here). He took a look at the mag wells checked fit with a magazine, and did a swap right there on the spot! |
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