Failure to Eject anyone?

[Listkeeper]

Has anyone else had failure to eject problems with their 450? I have shot my rifle twice. The first time (this past summer) the glass in my Bushnell Red dot sight shattered on shot #7, so I had a very short session. I think it had shaken loose enough for it to receive a good kick. I had the rifle at the range this weekend (with new optics) and experienced a failure to eject the spent brass several times. I have shot only the Hornaday 250 grain FTX ammo thus far. I probably had 10 failures out of 50 rounds.

Most of the brass made it partly out of the ejection port but got stuck as the bolt carrier moved forward. It looked like the stovepipe jams on a semiautomatic pistol - but out the side and not the top of course. Since it started jamming on round #10 I wouldn't think it was dirty. It was VERY cold out, I think it was in the 20's if perhaps that could affect the action.

Any help would be appreciated. Thannk you

[BillytheKid]

I have not had that problem with my .450b, however, back when I was pistol shooting many years ago, my extractor hook broke, and I got a lot of "stove pipes"

Hope that helps.
Bill

[dale]

did you tear it down & clean & lube when you got it? I took mine out the day it came and 2 did that out of 5 before i realized it was dirty.
my upper came new from bushmaster all gritty and funky...slicker than snot after clean and lube.

[bushmeister]

This sounds just like my first post here. My problem was that the gas block was not tight and became misaligned about the 5th shot. This is real easy to check. Just pull out the allen screws that hold the gas block down, and get a flashlight and look in there. You can see where it should line up with the divots in the barrel. If it's not lined up, you will be able to tell. Line it up and put a drop of blue loctite on the allen screws when you put them back in.

[bushmeister]

Oh, and welcome to the board!!

[Hoot]

Well, since we're fielding ideas, is your mag holding the next round up so high that it is dragging on the bcg or spent round. Easy test. Feed one in from the mag, remove the mag and shoot. Repeat as many times as it takes to feel that you are not experiencing FTE anymore. Also, is it worse when the mag is full, last round, both? +1 on a thorough cleaning and lube. I make my own from CLP and tungsten di-sulfide (WS2) powder. scrub it in with a nylon detail brush, then wipe off excess. You can also use a molybdenum di-sulfide (MoS2) bearing grease, but tungsten di-sulfide is slicker. 723 rounds and not one FTF/FTE other than a few short cycles from experimental light loads.

Hoot

[Archie]

I have not had any problems with mine whatsoever. I would say that your problem is with your gun, rather than the round or the way it behaves in and of itself. If nothing here helps out, keep looking at the gun.

I believe the post by Dale hits your trouble right on the head, though. Even if you did clean your gun when you got it (which you should do with every gun before you shoot it), you might have caused your own trouble after cleaning. As a coyote hunter (always out in COLD nights), I have learned over the years that a rifle needs very little oil and even less grease to function happily over it's lifetime. I have refurbished and saved a half-dozen rifles over the years that made it to the deeply discounted rack (or super cheap classifieds) simply because someone thought a bunch of oil - or worse-yet grease - "couldn't hurt". I would get the guns cheap after they "missed the buck of a lifetime" or were afraid to tear them apart to find out why the failure or funky behavior happened while on the range.

Dirty grease + cold weather = Failure to Operate Properly.

I have actually had a friend bring over a .30-06 that would not fire at all when the trigger was pulled in 85 degree weather. He had bought it from a "friend" for $20, and was told it was "unreliable", but functional. It would not function on my range no matter what we tried. I tore it down and cleaned it up. The bolt and it's guts looked like they were smeared with black tar and rolled in the dirt. Since we cleaned it over a year ago, my buddy has not had a single missfire with it, and has used it often. Best deal he ever got on a gun - and I got a free lunch and the satisfaction of helping out a friend.

AR's have a pretty simple teardown process (by design) and you can find printed directions almost anywhere for them (yes, even the owner's manual), so tear it down and clean up all greases and dirt. This time of the year, you can skip the grease unless you plan on really letting the lead fly. Just a real light gun oil (NOT WD-40) on the mating/sliding surfaces only - skip oil anywhere it is not absolutely needed this time of year. In the summer you can grease the sliding surfaces and oil anwhere else, including the firing pin, but strip and clean it next fall before using it in cold weather. Actually the dirt and debris that the oil/grease may attract will do more damage to your gun than normal use would do to it without lube. The idea of oil in the summer is for rust prevention as much as anything else.

I have yet to wear out anything on any of my AR's, and I have also never had a failure to fire or feed while in the hunting field yet either, and I have put a LOT of rounds through them, including one night last winter when it was -20 and fairly windy - I was only able to stay out until 3:00 am that night it was so cold...

Clean it up and your trouble should go away. If not, you will probalby find an ejector problem when you tear it down to clean it, thus solving the problem anyway. I would say it is a 95% liklihood that the problem is one of these two issues. Another possible problem might stem from the Buffer/Buffer Spring - and they would be easily eliminated by a visual check while you have the gun torn down anyway. Their job is to be sure the gun goes into battery after reloading, and a problem here would shurely result in a stovepipe. Good luck with the solution and I hope you find it soon. What a disappointment it is when you are looking forward to a little mayhem, and Murphy stops the show in it's tracks. That sucks for me and I just walk out the front door to shoot. It must be 20 times worse when you have to get in a car to go to the range!!!

[Listkeeper]

Archie, Hoot, Bushmeister, Dale, Billy,

Thanks for all the advice! I'll tear this thing thing down and clean her very thoroughly. My wife is out of town for 2 days so I actually have some free time to do it. The drive to the range is an hour each way so it might be a couple of weekends before I get to shoot it again.

One more question ... the fit between the upper and the lower is very loose. Anyone have any ideas on how to fix that? Are there shims or fatter pins? I did buy this rifle new just in case you were wondering.

[Jim in Houston]

I had several failures on my 450b the first (and only) time I had it out. One was a stove pipe and the others looked like failures to eject (i.e. next round forced up against the spent casing before it could get out the ejection port. I am going to shoot it again before I do any corrections, but I have had this problem on my Bushmaster XM15 5.56. I replaced the ejector spring in the bolt carrier with a beefed up version (availalble from Brownells or Bushmaster - at least for the 5.56, maybe it is the same for the 450) and also bought the little rubber donuts that go over the spring, although it was not necessary to use them.

Having replaced the ejector spring with a sturdier version, I had no further problems with failures to eject. If I have that trouble next time at the range, I will go that route first. I did clean the bolt carrier and checked that it was well lubricated before I shot the rifle, but I still had the problem - maybe one in twenty rounds.

Note, Bushmaster has a FAQ on their website that goes over the various kinds of feed and ejection failure symptons.

[bushmeister]

As for the play between the upper and lower, I installed an accu-wedge that tightens it up nicely. You can get it from Bushmaster for about $6.