Bushmaster problems?

B

buzz_knox

New member
A friend has a Bushmaster pre-ban carbine with a feeding problem. On occasion, the bolt won't strip off a round from the mag. On other occasions, you have to use the forward bolt assist to fully seat the bolt. I've looked at the mags and they seem tight, with the followers sticking on occasion. The mags are supposed to be all gov't contract mags new in the pouch, and include Center and K brand (not sure of the proper name). They've all got the black followers.

Any suggestions? My friend doesn't want an expensive hanger queen.

Also, if he takes this weapon to a gunsmith or sends it off, will a 4473 have to be filled out on it? It was a private sale to begin with.
 
Make sure that: the bolt and carrier are lubed, you have GOOD magazines (I use Colt) and GOOD ammo (no third-world junk)and the gun is CLEAN, especially the chamber. DO NOT USE the forward assist on an M-16/AR-15 weapon. If you do so and have a bad round or a filthy chamber it WILL mean a trip to the gunsmith. Bushmaster mag wells are GI spec and many after market mags do not seem to work well. Good luck, Rob
 
sound like some CLP will slick it up...
follow the TM

has the gun's mag catch been twiddled with?
is the gas tube straight?
how are the gas rings?
You might try a green followered mag or a thermold

Is the gun in CA?
A 4473 is not required for repairs but in CA gunsmiths will need an "assault rifle" repair permit
 
After properly lubing the weapon, the FIRST thing I would do to USGI magazines is replace the magazine springs. These springs are cheap and 99% of the time will return a magazine to its brand new functioning condition.

CMOS
 
Everything you have said suggests that the bolt carrier isn't moving forward as fast as it should. The most likely causes are that it is encountering too much friction from a dirty or poorly lubed upper receiver. It could also be the result of a weakened buffer spring. I'd also take a look inside the gun to see if there is anything loose that might be preventing the bolt carrier from moving forward easily.

I'd use some gun scrubber and a bristle brush to scrub out the upper receiver where the bolt makes contact with the sides of the receiver. Do the same to the bolt carrier.

After that I'd zap the upper with a little Remington Dri-Lube (spray can) or a light coat (one drop each side, spread it around using a semi-absorbent cloth) of CLP. Apply some Tetra Gun grease or a light coat of CLP to the bolt carrier.

If this doesn't fix the problem, then replace the buffer spring (pretty cheap repair and no gunsmith necessary).

If you STILL continue to have problems, then I'd start marking the magazines being used when the malfunction takes place and checking to see if the problem is being caused by a bad mag.
 
Is this happening with many different mags just with 1? I had a problem with my Colt until I polished the feed lips of the mags with a piece of Scotchbright, there was just a bit of a burr there.

Bri
 
Buzz, try this first.

Hinge open the rifle like you would for cleaning. Without unlatching the charging handle, move the bolt carrier to the rear as far as you can. Point the barrel straight down, and let go of the carrier. Don't push it forward, just let it go. It should go fully into battery without any assistance.

Now, try it again with the barrel held at a 45 degree angle. If the rifle is fully broken in, it should still close by it's own weight. If it does not close, degreasing and relubing the carrier may help, or you may need to alter some parts by bending or deburring as other people mentioned. The gas tube/gas key fit is easily disturbed.

The other thing to look at is the ejector. It should not protrude past the front of the bolt, and it should be able to be pushed back flush with the bolt face. If the ejector retaining pin breaks, the ejector can hang up, causing chambering problems. Depressing the ejector with a punch and letting it pop forward a few times will tell you if the pin is still whole.

Hope this helps.
 
I have a chance to pick up Colt demo 30 round mags for $24.99. Will these fit and function in a Bushmaster? If so, would that potentially eliminate some problems?
 
Yes the Colt mags will fit. Whether or not it will fix the problem or not is another story. For reliabilty issues I would stay with the GI contract magazines, and not use Thermolds or Orlites. The Centers and Okay mags that you have are GI contract. By the way, Okay made the Colt mags. Same mag, just a different stamped base plate. Before going to a smith, I would clean and lube the weapon very carefully, and especially clean the bolt and lug area. Take a shower with it if you have to, and I am serious. Next, I would take the magazines and replace with Wolff 10 percent extra power springs. Then I would replace all the black followers with green ones. The green ones are ant-tilt, and they are the current mil-spec. When dismantling the mags check feed lips for cracks and burrs. Also check the inside of magazine tube for burrs, or the outside for dents. If the tube is dented, I would get rid of it. Lets move on to ammo. The best choice here would be Winchester Q3131A. Do not buy the Q3131 because of too many reported problems with it. The Q3131A is current US mil-spec ammo. The AR not feeding properly could all be related to magazine problems. Not chambering can be related to ammo that is out of spec. I would not use reloads in my AR. Reloads in an AR has caused me nothing but trouble. Sling Shot
 
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