Brass over Bolt malfunctions.


Last Sunday I helped a shooter at the range with a brass over bolt malfunction.  Brass over Bolt is a rare malfunction where a casing(live or spent) gets stuck over the bolt and between it and the charging handle.  I’ve learned that the quickest way to clear one of these jams is to reach up in the mag well with your middle finger and put that finger on the bolt face holding it back.  When that bolt carrier group is held back, you can run the charging handle forward, and knock the stuck casing/round free.

Shawn and I both agree that while the brass over bolt malfunction can be cleared quickly, in a faster paced or close range fight you may be better off transition to a sidearm if you have one available to you.

While I was in the Marines with all these used and abused M16A2 & M16A4s and old worn out mags and we never saw or heard of a brass over bolt malfunction.  Now the funny thing is, every time I have helped someone with a brass over bolt malfunction I noticed they they were not using cheap or worn mags, they were using Magpul PMags.  I have discussed with Shawn and he too noted that brass over bolt malfunctions seem to be rather new, and seem to mainly have happened in AR15s using PMags.

So, have any of you had the brass over bolt malfunction and what mags were you using when you had it?


  1. I had two yesterday. Had one the previous day, possibly two. Was using old GI mags. All were with live rounds, not empties. The last one was in there really tight. Needed the method of :Remove mag, collapse stock, hold back on charging handle, pound stock on ground.

    Anyone have thoughts on the causes of these?

  2. It happens in pmags a lot because you can physically fit 31 into a 30. When the bolt passes over during charging the mag pops this over-tensioned round out and above. I’ve seen it mostly in the saw and with gi mags. If its a spent round its usually from someone putting their fingers over the ejection port while using the mag well as a grip. I’ve also seen worn out mag lips that did it if you tapped the mag in too hard.

  3. I just had my first one yesterday. Had to pound the stock on ground while pulling on charginghandle. Was using a cheap off brand mag.

  4. Had one today with an AR pistol and Stoner mag. Weirdest thing though… I laid the pistol down too hard on the bolt release and tried to stop it by grabbing the charging handle. This one is all on ME!
    I’m hoping to slam it loose at home. They wouldn’t let me do it at the range.


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