Other than falling out of the gun or not feeding a round out of the mag at all, what types of malfunctions have you all witnessed that was caused by a mag not fully locked in place.

I'm tyrying to figure out another wierd malfunction with the Bushmaster yesterday. We were doing some rapid fire drills with mag changes and transition to pistol.

It seemed like maybe the mag was not up and locked all the way because the rounds were being pushed into the cases when riding up onto the feed ramps.

I was using the Remington 55 gr fmj from Wal-Mart (green/white box) and I don't think that stuff is crimped. Although the bullet has a cannalure. Could be part of the problem?

Magazines were two new USGI 30 rounders w/green followers.

After the malfunction I reloaded the mags and ran the drill again, making sure that when I changed mags that they were fully locked in place and I had no malfunctions that time.

When we had the malfuction my son was shooting it very fast. Can you shoot a semi AR15 too fast so as to induce some kind of malfunction? I would doubt it myself.

The rifle and the mags were clean but I'm going to clean the mags and get some M193 or Q3131 etc and try it again.

Thanks for reading,

EMSflyer

Quoted: I was using the Remington 55 gr fmj from Wal-Mart (green/white box) and I don't think that stuff is crimped. Although the bullet has a cannalure. Could be part of the problem?

I bought two boxes (40 rounds) of the Remington UMC 55gr green-white box MC (metal case, I think the same as FMJ maybe not) to try it out. One of the rounds had an oversized case. The case was too long and covered half of the bullet compared to a "normal" round.  It would not chamber.  Never again with that crap.  Thats the only round I've seen that bad, especially out of factory ammo.

It could be the Remington ammunition. I used the same stuff. It's called Remington UMC. Green and White box. The kind I used was Hollow-Point however. With that stuff I was constantly getting jams and my Bushmaster has only about 100 rounds through it and is 2 weeks old. Maybe try it with M193 and you will probably see better results.

Quoted: Other than falling out of the gun or not feeding a round out of the mag at all, what types of malfunctions have you all witnessed that was caused by a mag not fully locked in place.

The mag is either locked and stays in the rifle or unlocked and falls out.  There is no "in between".

Try something simple. see if the gun is getting enought gas.
-load 1 rd and insert mag
-fire round and see if bolt locks open on mag
-do this about 10 times

if your bolt does not lock back you have a gas problem. check your Gas key.

Just a thought.

Quoted: if your bolt does not lock back you have a gas problem. check your Gas key.

Check to see that your gas key is properly staked (or staked at all).

Quoted: I was using the Remington 55 gr fmj from Wal-Mart (green/white box) and I don't think that stuff is crimped.

It certainly is crimped.  ALl factory ammo I've seen, with the exception of match stuff like BH and Fed GM, has been crimped.  All factory hunting ammo I've ever bought from Remington, Federal, and Winchester has been crimped, and most of it was cannelured as well.

"Other than falling out of the gun or not feeding a round out of the mag at all, what types of malfunctions have you all witnessed that was caused by a mag not fully locked in place"

On one occasion the bolt pushed the cartridge a short distance into the chamber then the bolt went over the top of the cartridge rim and smashed the case against the barrel extension.  The case was deformed enough that it would not chamber.  I pulled the charging handle back, pushed up on the mag and heard it lock into place. Once I cleared up the malfunction I stepped in hole and fell down nearly dropping my rifle in the creek. After that I called it a night and went back to the house.  All from not having mag firmly locked in place.

D348,

That must be what happened to us.

Sounds just like what we saw with my bushmaster.

Kid got in a hurry with mag change and did not make sure it clicked in.

When it was my turn I went a little slower, made sure mag was locked and no problems.

Thanks,

EMSflyer

Edited to add......

My son took some exception to my refering to him as the "Kid". So I told him I would edit to add that although he is a teenager (Kid in most folks eyes), he's been shooting USPSA/IPSC for the last 9 or 10 months and is a very competent shooter in his own right. Except for making sure the mag was fully locked that time...