Hi everyone, I’ve been reading through these forums for a while but just now got around to registering. I’ve been having issues with a used Bushmaster that I bought back in Dec. '08, and figured you all may be able to help.
I was well aware of the “chart” before I went shopping, but there were only five options at the store. Three Bushmasters of different configurations, a left-handed Stag, and a Doublestar w/out chrome lining. I wasn’t keen on Bushmaster, but seeing as my options were very limited I chose the only A3 upper model in the store (the others were an A2 and some “limited edition” model for big $). Chalk it up to unfounded worrying, but it’s what I ended up with. It was a police trade-in, and I checked the chamber as best I could before I bought it; I have no idea how many rounds went through it prior, but you could tell it was well-used. It is also a “ban” configuration, with no flash hider or bayonet lug (16" barrel, carbine gas system), so to me that means it’s also fairly old. Now on to my point: the darn thing misfeeds every time I shoot it. The first magazines I used were from Brownells, with the green followers. It jammed with those starting from the first time I tried chambering a round; I decided to cut to the chase and bought three Bravo Co. mags with the gray Magpul followers. It jammed with each of those the first time out as well, though as I used them more the jamming became less frequent and seemed to be only happening with the first round(s) being chambered. The most common jam type was double-feeding. The spent casings eject fine and it shoots straight, but due to the persistent jamming I’ve lost confidence in it.
I’ve only been able to come up with three possible reasons for the jams: 1) the magazines have such good springs that there is too much force pushing the rounds up and thus causes the jams; 2) there is something wrong with the bolt/bolt carrier that is causing it to snag more than one round; or 3) the buffer is the wrong type (it looks to be a standard buffer) for the carbine gas system (but the rifle cycles fine, and I don’t see how a buffer problem would only affect the first rounds being chambered). Do any of those scenarios make any sense? What could be doing it?
I mostly want to figure the problem out because I’m planning on getting a different upper, most likely a BCM, and if I sell the BM upper I don’t want to pass a lemon on to someone else, and also if I have to use it in the future for some reason I want it to work right. Sorry for writing a novel, I just like being descriptive Thanks.
The most common jam type was double-feeding. The spent casings eject fine and it shoots straight, but due to the persistent jamming I’ve lost confidence in it.
Need to confirm exactly what your malfunction is. You have two live rounds being released from the mag at one time?
A lot of times when folks call the malfunction a double feed, they are actually talking about a failure to extract. This would be a fired case remaining in the chamber and a live round feeding on top of it. This is commonly due to a weak extractor spring.
Also, many Bushmasters have weak staking of the gas key and develop a gas leak as it loosens up, which can cause various malfunctions. The test to see of the gas system is functioning correctly is to load 1 round in the mag, fire it and see if the bolt locks back on the empty mag. If the system is short stroking, there is insufficient gas pressure to drive the BCG all the way to the rear.
Eric, yes it appears that the first two live rounds are (or try to be) fed at the same time, and end up in a traffic jam trying to get into the chamber. The ejection is fine and strong, as a matter of fact I don’t think it’s ever had a problem getting a round out. The gas key appears to be well-staked, whether I was lucky or whether a police armorer did it is anybody’s guess. I’ll see if I can take a picture of it and post it just to be sure.
Edit: sorry about the blurry pic (cell phone camera) but hopefully it is enough.
556, I typically load the full 30 in the mag. After one trip to the range, I had a couple of mags with about ten rounds or less in each, and the next time out I used them and, IIRC, there weren’t as many feeding issues. I haven’t tried only loading two in there, I’ll give that a go next time I shoot. It typically happens with most mag changes, but once the initial jam is out of the way the rest of the ammo feeds okay, again, most times. Thinking back on it, it seems like most of the jams occurred with full mags, and before I had done much shooting. And yes, it strips two from the mag at the same time.
Bushmasters are chambered for 5.56 and .223. Is it only happening with one mag or all of them? I had a bad mag that was included with my bushmaster, after I got rid of it no problems feeding what so ever. I was having the same issue as you.
I’ve only used two types of ammo so far: UMC .223 and Federal XM193 5.56mm (both 55gr FMJ); the receiver says both chamberings. When I load the mags, I simply push the ammo straight in through the feed lips, one at a time (in other words, I don’t use a mag loader); once it’s full, i give it a little tap/shake to seat the rounds to the rear of the mag so the tips aren’t hitting the front, and insert the mag into the rifle. For what it’s worth, I have the bolt locked open before I insert the mag, and release the bolt catch once the mag is in. I give the forward assist a little push, and away I go. I wonder if the open bolt at the beginning has something to do with it?
I’ve tried five mags with it so far, two of the Brownells with green followers and three Bravo Co. with the Magpul gray followers. Feeding problems have happened with all of them, though the Bravo Co.'s are better and seem to run ok after the rifle has gotten the initial jams out of its system. It’s like the rifle doesn’t like having 30 rounds in it for some reason, and chews up the first couple, but feeds okay after that. I need to get it back to the range and do some more evaluations so you all have more to go on. Thanks for all the feedback thus far.
When you put that first mag in (with the bolt locked back) you are not smacking the bottom of the mag or anything like that, are you?
Load your mags to 28 rounds, lube your rifle well and try again. Often double feeds are because of magazines, but other things can cause them. I saw an issue similar to yours last summer. It was a combination of things…
Hmm. I don’t think I smack it, but I do usually give it a small push/tap to make sure it’s fully seated. Nothing that I think would dislodge rounds or anything like that. I’ll try to get to the range as soon as I can, and try the 28 rounds instead of 30; I also picked up a PMAG, so I’ll give that a shot just in case there’s some freak malfunction caused by the metal mags.
Be carefull with P-mags because often they will phsically allow 31 rounds to be inserted, but then they will not seat correctly into the lower and/or malfunction. The_Katar saw this over and over again at the group meeting we had a month or so back. Make sure when your P-mag is full that you can push the top round about 3/4 of a bullet width into the mag before hitting the hard stop. It your last round barely moves down, your over loaded and asking for trouble that will be blamed on the mag. I’ve put a couple thousand rounds through my P-mags and not ever had an issue, but at that meeting I watched other users have big troubles from this over loading the mag issue.
try pulling the charging handle back and releasing instead of the bolt catch. the extra 1/4" or so of bolt travel that results makes a big difference in chambering that first round sometimes.This is the technique I use all the time and it does seem to eliminate those 1st round out of the mag stoppages
When my guns start having a problem stripping the first round off of a fresh magazine, I check the buffer spring first. Measure your buffer spring length. I forget the length of a new one, but I want to say if your current spring is less than a foot long, it’s time for a new one. Cheap buffer springs can get compressed as early as 2000 cycles. Get a good one and it’ll last 10 times that, easily.
I’ll give that a shot as well, CAVDOC. I’m going to see if I can get out there on sunday or early next week to try the methods you all have suggested. Thanks again.
Alright, I finally made it to the range yesterday. I tried loading the magazines several times with twenty-something rounds, and viola! no jams! No failures to feed or eject, it ran like a top. I even had someone else that was with me try it out, and they didn’t have any problems either. I guess not loading those extra couple of rounds really made the difference. Thanks to all of you for your input and ideas, at least now I don’t “have to” buy another AR.
Thanks.