Gas Tube/Gas Key Making Contact

[STAMarine]

A couple of days ago I was shooting drills when I had a failure to fire. I tap, racked, banged, and continued on. A few more rounds later, the same thing happened, and again, a few more rounds later, the same thing. Now, I admit, I should have broken my rifle down before this point and diagnosed the problem, because I had and estimated three thousand rounds through it without a single problem. However, I had done a lot of shooting lately without cleaning, only lubing, so I figured it was just built up carbon and gunk that was sticking things up. However, when I broke the rifle down I found that the gas tube opening had been peeled back on one side, and the gas key had been peeled back on the corresponding side. The failures to go into battery was obviously caused by the damage preventing the tube and key meeting up properly.

I ordered a new tube and key from BCM yesterday, and ADCO has said they will fix it no problem. I know, I should be able to fix it myself, but this is my go to rifle, so I want to make sure it's done right. I've never had this happen before, so I wondered if someone could diagnose the cause and if there was a preventive action to keep it from happening again once repaired.

The rifle is a BCM 11.5 inch that I sent the upper to ADCO for removal of the original front sight base, and installation and pinning of a BCM low profile gas block. Again, this was all when the upper was new, and since I have about three thousand rounds through it without a single malfunction, it is obviously no fault of BCM or ADCO. I only name drop to show this wasn't a bubba built or a bubba wrenched upper. Ammo was Winchester 5.56 55 gr. I was also shooting suppressed when the trouble started. Buffer spring was an almost fresh Springco white with H3 buffer.

If this is something that just happens, then so be it. I just wanted to check to see if there was something that I could do going forward to prevent it from happening again.

[MegademiC]

Could have had something get in there to cause it, like a blown primer or something.

[tehpwnag3]

Please share a picture of that. I am wondering if there was slight misalignment that slowly worked it's way to failure.

[STAMarine]

Please share a picture of that. I am wondering if there was slight misalignment that slowly worked it's way to failure.

Will do. I'll take a pic with my phone when I get home from work. I'll post it if I can figure out how. I should have from the get-go, but I haven't posted a pic before and I didn't know if this was something that happened on occasion.

[Iraqgunz]

It sounds like something was out of alignment and the tube was damaged by impinging against the carrier key. Pics would be good. If it's simply the gas tube, replacing it is pretty simple and straightforward.

[STAMarine]

gas key.jpg
gas tube.jpg

Here are the promised pics. I know it doesn't look terrible, but it certainly was enough to prevent the bolt from going into battery.

[tehpwnag3]

Not sure what happened there. Looks like the key rammed into the tube. Time for a new key and gas tube.

[STAMarine]

Not sure what happened there. Looks like the key rammed into the tube. Time for a new key and gas tube.

I think the same thing. What I am wondering, though, is what caused it since I have more than enough rounds through it to gauge it as a reliable weapon. Is there a component or combination of components or action that caused it that can be changed to prevent a future occurrence after I get it fixed?

Anything mechanical can fail, but is this something that can be prevented?

I wish I had kept a hard round count like I say I will after every new purchase, but thus far I've only done with with precision weapons. At any rate, I have enough rounds through it to say it's reliable, but not enough that wear can be blamed.

[Clint]

It's a bit hard to tell from the pictures, but it may have been a loose primer wedged between them.

Check some of your fired brass for missing primers.

The tube should be replaced for sure.

The gas key MAY be fine with a little clean up, depending on how deep the damage is.

[STAMarine]

It's a bit hard to tell from the pictures, but it may have been a loose primer wedged between them.

Check some of your fired brass for missing primers.

The tube should be replaced for sure.

The gas key MAY be fine with a little clean up, depending on how deep the damage is.

Ah, I've already ordered a tube and key for replacement. It's a small price to pay for reliability, especially since this is my go to rifle. I did police my brass, so I'll check them tonight. Thank you