Colt commando upper starting to get froggy

AR/M4 AR Pistols & Pistol Caliber ARs
1

I had two guns start to act weird yesterday!

My recently SBR’d AR with Colt Commando Upper had two odd malfunctions yesterday. First, I had a failure to ignite. I didn’t notice if it was out of battery. I just kicked it out. It worked on the second shot. The second malfunction was an empty case stuck above the bolt, oddly, with an unfired cartridge in the chamber (the empty case was sticking out of the ejection port.

Background,

I have had this upper for a long time (about 7 years), I have shot if with thousands of round of steel, 22, brass, etc. It has gone through many phases…

https://www.m4carbine.net/showthread.php?236505-Resprayed-my-AR-pistol-It-is-fun-to-see-how-this-gun-changes-through-the-years&highlight=

I don’t clean it religiously, but I do clean it every few outings. It isn’t disgusting right now.

I was running it with 55 grain Hornaday Frontier. That ammo has run perfectly in every gun. I was shooting it with my Surefire Socom as usual. I will say recently I have been shooting it with Tula steel without the suppressor and it was running fine. I wonder if it is finally over gassed?

So, AR masters…What say you? Give me your best diagnostic tips and I will do what I need to do. If I have to replace the barrel and gas system I will probably just buy a whole new assembly. I really dig the way I have it setup these days…

IMG_2910 by stoiclawyer, on Flickr

2

Check your extractor, replace the extractor spring and maybe install the little rubber gasket thingy.

If all else fail, give it to me.

3

Could also be the old shooting brass after shooting steel thing. Clean the chamber thoroughly, try again.

4

You probably need a new barrel.

5

That’s what we (in the high speed tactical community) call a "CLUE)!!

6

Is that not good ammo in your experience?

7

There was quite a bit of chatter in another thread about it being poor quality. The accuracy is awful, but the stuff we have shot did run ok. The bottom line is the ammo would be my first guess.

8

Yes, give the extractor a good cleanjng and inspection.

If the extractor spring has over 6,000 rounds on it, replacing it with a new Gold spring would be a good idea.

9

Clean, lube, another known decent brass ammo. If a no go, I’d go with a quality extractor assembly replacement.

10

I cleaned it up paying particular attention to the extractor and chamber… Replaced the buffer spring (which was visibly shorter) and fired 100 rounds of federal 55. Functioned fine but noticed it was ejecting around 1 o’clock. Might be time for a h3-4 buffer?

11

Try replacing the extractor spring first. If the buffer spring was done, there’s a better than fair chance that the extractor spring is too. And it would explain the forward ejection.

12

That will be my next step then.

13

A BRT gas tube is a MUCH wiser purchase… assuming the 1 o’clock is indeed too much bolt speed. Heavy buffers as a fix suck royally compared to correct gassing.

14

I like it. I wouldn’t mind swapping it out but I have no idea what port is on the 11.5 commando.

15

Clint has a sizing question series to get you rolling. Current port is irrelevant.

16

Yes, if a new extractor spring doesn’t bring it back to proper function, and it’s still ejecting to 1:00, the next step would be to address gassing.

An EZTUNE is a great fix if the gas port is eroded but the barrel is otherwise fine.

17

^ Can confirm. Happy with both my older gas block insert and my gas tube. Used to think adjustable gas blocks were “cool” but the shiny wore off pretty quickly with the frequent tinkering and cleaning. Set it and forget it is the way to go if it works for your application.

18

Thanks so much for the help brothers. I went ahead and dropped in a Daniel defense bolt I had in my doomsday bag and it changed the ejection from 12:45 to 245 to 3. It’s also much more forceful. I swapped the old bolt back in and it went right back to pissing it out at 1 o’clock. Thanks very much. ! This Gun has run great for a long time, so I’m not gonna hold it against it that a little couple of springs got tired!

19

Nice. Glad it was an easy fix.

20

Glad to see it squared away. No concern abt brass ejection direction. That old ejection path “pie chart” is garbage.