New Bushmaster jamming up on me

[AlaskaErik]

I just fired my new Bushmaster for the first time this weekend and had four jams. Basically, the spent cartridge didn't eject before the next round fed. Best guesses on the problem? Wish I'd taken pictures of the two cartridges jammed up. I just took the mag out and either pulled the jammed rounds out or used the charging handle. I fired a total of 150 rounds. Boy, was that barrel hot! I don't recall my M-16 ever getting that hot. The ammo used was American Eagle .223 REM 55 gr. FMJ boat tail. The first picture shows the markings left on the neck of the rounds. On the second picture, I rotated the left-hand round 180 degrees to show the indentation on the other side. Thanks to all.

 

[Bartholomew Roberts]

Those pictures aren't that helpful. They have the twin gouges because they are trying to feed into the chamber; but they can't because the spent cartridge is in there, so the lugs of the bolt dig into the side of them and cause the twin scratches.

Your problem is extraction. You mention the rifle was hot - and heat can cause extraction issues because as the chamber becomes hotter, it takes longer for the brass to shrink away from the chamber walls. Do you have any pictures of the base of the case that did not eject? Did you get failures to eject more towards the end of the 150 rounds, towards the beginning, or all through?

I don't really have enough info to do much more than guess; but you might try an O-ring, Defender, or enhanced extractor spring. These are all cheap fixes that might help your problem.

 

[glockman19]

1) did you clean and oil your rifle before shooting it for he first time?
Strip it down clean and oil the bolt carrier, firing pin and everything else then see what happens.
2) are you using Old New mags?

 

[Will Learn]

It might be short stroking. Make sure that the lugs on the gas key aren't loose, also check the extractor spring for deformation.

 

[Bartholomew Roberts]

Another thing to consider is if you are using the light gun oil that comes in one of those all-purpose cleaning kits, those sometimes aren't up to the task of heat in a semi-auto weapon and burn off quickly, leaving no protection behind. Some type of CLP product is probably a better choice for lube. I'm using Slip 2000 Gun Lubricant myself; but Mobil One works too.

 

[v8stang289]

What kind of upper is it? A good friend of mine just had to send his bushmaster predator upper back to the factory because something was wrong with the gas system and it was causing it to short stroke and not feed properly. I think he said the gas port was too small or off center. You might want to talk to bushmaster about it.

 

[MMcfpd]

The lube suggestions above are good and important, particularly for a new gun. And, as it is a new gun, you might well find that, properly lubed, it just sorts itself out after a couple of hundred rounds.

 

[david_the_greek]

haha oh man I think i know what this problem is. sorry I don't mean to laugh its just that I bought a brand (almost) new AR and had what sounds to be the same problem. boy was I PO'd. thought how stupid I was that I bought an AR at 2x the price of an AK. if your problem is the same as mine was, then it is in the extractor itself. don't worry its a quick fix and will cost you next to nothing. I'll try to take some pics of this as well. basically you need to open up your rifle and put a #60 O-ring on the small extractor spring within your bolt. 100% fixed my problems. I am not sure how to post pictures sactually and it seems more coplicated than I can figure out. I'll try to email them to your name or if ya drop me your normal email I'll get'em to ya

SORRY forgot to add that email will becoming from an [email protected]

 

[Outlaws]

Just as a side note, that looks like some crummy ammo....as American Eagle typically is.
But just look at the seating difference in the three bullets. Maybe that was from it hitting the unejected round, but I would take a look at the rest of the box anyways just out of curiosity.

 

[Onmilo]

Underlubrication.
Parts may be a bit rough from the factory assembly.
Ammunition may have been old.
Factory may have used a carbine spring instead of a rifle length spring or vice versa.

I lube rifles for the first time with Tetra Gun Grease mainly use a mixture of Tetra Gun Grease and M-Pro 7 CLP afterwards.

My guess is start with the lubricant.