Am I looking at a gas block problem?

[Clint]

Hi Dan,

This is pretty typical of a loose fitting, low quality generic gas block.

Replacing the gas block and tube with quality units should take care of it.

While you're in there, measure the gas port diameter and the distance from the shoulder.

Report back to make sure it's reasonably sized and located.

[Iraqgunz]

First thing that sticks out, since we can't see what it looked like before disassembly. Barrel is not dimpled. I suspect that the gas block could have been seated incorrectly. I would also venture to guess it is not very snug on the barrel.

I also wouldn't be surprised if the gas tube orifice is out of spec and causing gas to leak as well.

[ouchonyee]

Maybe gas key on carrier is plugged up somehow?

[BocaDan]

Greetings folks,

Here's an update to an earlier thread I started which many helpful members here chimed in and gave opinions. Original thread for reference: https://www.m4carbine.net/showthread...-block-problem

I finally had a chance to reassemble the upper and took it to the range. I've installed a better gas block, new gas tube and had the barrel dimpled by a professional to accommodate the new gas block. Not sure if blue was the right way to go but I loctited the gas block screws pretty tight.

I am happy to say that after 60 rounds earlier today (40 American Eagle + 20 Brown Bear) I had zero extraction, ejection, cycling problems. Tried with a single round in the magazine about a dozen times and the bolt locked back every single time. Tried with 2 magazines to be on the safe side - a 2nd Gen Magpul & a H&K one. Zero fails...

I also noticed something else on the inside of the handguard when I took the upper apart to replace the gas block & tube. See the areas marked with the arrows? They were in the vicinity of the gas block and just accumulation of what I guess to be burnt powder. So unless a little bit of gas is really supposed to seep out of that region, it was definitely a leak / poor seal...







Thank again all!

Cheers

[jmoore]

I keep misreading the titled as "Fixed lingerie issues ....."

Damn - keep getting my hopes up!
john

[HansTheHobbit]

Blue thread locker won't hurt anything, but it won't help much either. The gas block gets way past hot enough to liquify it. If it's an aluminum block, be extremely careful if you ever remove those screws, or you're likely to take a few threads with you. In any case, don't spare the heat gun if you ever remove it.

Depending on how hot you get your barrel, red thread locker will most likely work, but this will pretty much be permanent in the case of aluminum, semi permanent in the case of steel. The dimple should be plenty to keep it in place, though. If you're really paranoid about it, then staking the screws is about the only way to make it foolproof.

[Benito]

Aluminum gas block? That is the craziest thing I've ever heard of.

[HansTheHobbit]

Aluminum gas block? That is the craziest thing I've ever heard of.

There are plenty of them out there.

[ST911]

Threads merged.

[redmist]

I repaired an aluminum gas block setup at a recent carbine course at LMS Defense. The student started seeing holes in his gloves! Surprisingly, the gun continued to function, however the hold on the rifle became painful after using it for a few drills. We took the gun down, and noticed that the aluminum gas block had eroded out the side from use, and formed a plasma torch of sorts. It actually melted a slot into the troy rail, and started to chew threw the students gloves. We broke the rifle down, replaced block with a titanium unit off my backup gun and continued on.

Ryan