Let me first start off by saying, yes these two incidents happened in two different Bushmaster brand M4's each of which I can say have 5.56mm chambers. The ammo in question is Federal AE .223 55gr. FMJ BT. It is a relatively recent lot, as the color used in the sealant seems to have changed from the red that I have seen in every round previously to a new blue colored sealant.
Let me describe each failure.
Incident #1 took place in carbine A (I could describe the carbine, but only if asked) It consisted of a round that failed to eject, it was wedged inside the upper between the bolt face and the back of charging handle, resting in the charging handle channel. Also against the bolt face was a round in the process of being stripped off the mag, but couldn't because the bolt's movement was mentioned by the aforementioned case. When popped out, the empty case had three distinct features. First and most obviously, the primer was missing, a scorch of blackened soot left in its pocket. Second, the case had a "belted" effect. Finally, the case showed very strong extractor claw markings, digging into the brass.
Incident #2 took place in another carbine, carbine B (Once again, if you feel it is necessary I can describe them both) This incident was much more mild. The empty case had simply created a sort of horizontal "stove pipe" where the top of the empty case was wedged against the front of the ejection port. This case showed no sign of belting, but again, the primer was blown out, not to mention the heavy extractor claw marks. Also, but I attribute this mainly to the stovepiping, the case head was crunched severely.
What is wrong with this? You have nearly identical issues happening in two different carbines, with the same brand and lot of ammo, at this point, I'm going to call it ammo and shoot the rest of this batch up. What do you'all think?


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Gotm4, I'll buy the BCM kit for now, and before I take a class, I'll definitely buy each of the items you listed (Well, probably more than 5 mags
)
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