Colt M4 Ejecting Into Receiver

AR/M4 AR Technical Discussion
1

Has anyone experienced this with a new Colt M4? A friend of mine just contacted me when this happened to one of the Marines he was training. The Marine had managed to install the bolt in the carrier with the extractor facing the opposite direction of the ejection port. When the bolt was checked (new from the armory by the way) the cam pin could be inserted from either side and no bevels were present. Just want to know if anyone else has come across this particular problem recently.

I will post some pictures as soon as I figure out how to get them off of my phone.

2

Yes I have heard and seen this happen and yes, it was 100% user/builder error on inserting the bolt in the wrong way when reassembling the BCG.

3

Was this on an actual military Colt M4 or M4A1, or something different? I’m only interested in experiences with issued hardware.

4

how the hell does that happen? I dont think you can put it togher that way

5

Right, definitely shouldn’t be able to; but my friend alluded to a possible new design change that somehow allows this to happen.

6

Pictures:

7

I highly doubt that Colt would make a design change for exactly this reason. It has to be a defect and needs to be reported ASAP.

IIRC the original M16’s had a bolt that would allow the cam pin to go in either way and it was changed for exactly this reason.

8

That is a bad bolt if you can install the cam pin the wrong way.

9

My thoughts exactly.

10

I’ve had it pop up a few times over the years.
It happens. User error and inspection fail.
Still, usually impossible to do.

11

I thought the cam pin hole in the bolt and the cam pin itself are tapered so that you cant install the bolt in that orientation?

12

+1 on the out of spec bolt. Should NOT be able to assemble that way!

13

I like to imagine that it didn’t fit, and the guy just forced it in there that way, and fucked shit up.

I know that probably isn’t the reality, but I’ve seen a lot of stupid people, and it was the first thing that came to mind.

14

If you give it to a grunt, he will break it. It is a constant like gravity.

Issued yes, to me no. I have never had this problem with newer gear though.

15

I hate it when people say that.
Accross every MOS, the 03XX occ field has one of the highest ASVAB averages and the highest T&R task completion of any occ field.
Yeah, there are still idiot 03’s, but taking the time to actually train people and teach them how to be self-sufficient goes a long way to preventing these kind of issues.

16

Also more 110 GT scores in the 03 field than any other MOS in the Corps.

17

Not that shooter though, apparently.
:sarcastic:

18

Unfortunately no…

Surprising though, given the group of individuals who were being trained.

19

The so-called armorer needs to have his balls smacked with a 5lb. hammer. That should have never been issued if the issue was known.

20

Heard of this, never seen evidence of it before. Huh, kinda neat…in the “that’s f**ked-up!” kinda way.

Definitely a good “teachable moment” item, for a switched-on NCO to do a hip-pocket class on weps inspection.

That the sort of thing that an armorer should be picking up during LTI, PFI, or which XYZ sort of interval/inspection?