The Firearms Forum banner

1 - 20 of 21 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter · #1 ·
Hello everyone.

This might be a stupid question, but here goes.

This is my first AR, I bought it used (perhaps a mistake) ... I'm no gunsmith, and I'm not very knowledgeable regarding AR parts.

After cleaning it, I was looking it over and noticed something that looks like a problem to me. It looks like the gas block has a blowout.

It's a 16 inch barrel, carbine length gas system, if that helps.

Any input will be much appreciated.
Thanks
253112
 

·
Super Moderator
Joined
·
42,021 Posts
It is kind of hard to tell what I am looking at. That does kinda look like a hole but not terribly sure. It also looks like the gas block is not back against the barrel "step down".

Have you fired it yet and if so, did it cycle OK? If it cycles, then the gas system is fine.
 

·
Super Moderator
Joined
·
28,582 Posts
There should definitely not be a hole there.
 

·
Super Moderator
Joined
·
42,021 Posts
Yeah, you got problems, but easy enough to fix with a new block and gas tube.

Just my thoughts, but it looks to me like the gas block moved forward that 1/8 of an inch and the continue firing (probably single shot) cause the blowout on the side of the block, actually I have never seen anything like that!!
 

·
Super Moderator
Joined
·
42,021 Posts
Get a quality gas block,never seen a gas block where set screw is exposed when tight.Never seen a hole either in a few 100 Ars.
That's probably why the blockis forward that little bit, the set screw worked loose and the other one may be gone!!
 

·
GUNZILLA
Joined
·
7,360 Posts
Looks like it was way over gassed. If your brass was ejecting at the 3 to 5 o'clock position it is ok, but if the brass was ejecting forward than it was over gassed because the brass was still in the chamber and the bolt pushed it forward before loading a new round. Looks like a heat treatment problem.
 
  • Like
Reactions: shootbrownelk

·
Registered
Joined
·
7 Posts
Discussion Starter · #9 ·
Thanks for the input everyone.

I also noticed that set screw sticking out... It was loose. I then removed both set screws to look... There are drag marks on the bottom side of the barrel. So I think your assessment is accurate Moody.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #11 ·
Any suggestions on what to look for in a quality gas block/tube?
Can you mix n match them, or is it better to buy together as a pair? As in - are certain design features meant to be used together for specific reasons?

The fact that it was overgassed to begin with, should I look into getting an adjustable gas block?

Thanks in advance.
 

·
Super Moderator
Joined
·
42,021 Posts
My opinion only - you don't need an adjustable block and if the gun was "over gassed" then it was the fault of the ammo and not really the gun. I have built about a dozen AR's and to be perfectly honest I buy the least expensive that I can. The $20 gas block does the same thing as a $100 gas block - that one just gives the seller a bigger profit.

Same thing with gas tubes, same-o, same-o, they are all just tubes. You might even be able to get that one off and reuse it but I have never had good luck removing the things! I have bought them off of eBay, from CDNN, from Sportsman's Guide, from Bear Creek Arsenal, and other places, like I said what ever was cheapest when I was looking for one. i am sure others will give you better info, this is just my $.02 worth.
 

·
Super Moderator
Joined
·
42,021 Posts
I got an email from CDNN this afternoon. I just opened it and see that they have the tubes for $8.99 for any size and the block for $19.99, which are both pretty good prizes.
 

·
Registered
Joined
·
5,664 Posts
I'm not suggesting to fire it to test this because I don't think that would be safe. I have to ask though. Did you fire it before this cleaning? If so, did it cycle? Like everyone else, I've never seen anything like that on an AR.
 

·
Registered
Joined
·
4,911 Posts
Just curious as to what brand of rifle is it or was it built? I know S&W are over gassed but I never heard of it being a problem.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #16 ·
Yes it was fired recently. It was cycling okay for the most part, but periodically I had spent casing not ejecting. Which makes sense, if a lot of the gas was escaping from the blown block.

It is a build, the upper has a logo that shows TNW. Not a company I've heard of.
The lower is Aero precision.
 

·
Registered
Joined
·
5,868 Posts
ALL 16" with carbine systems are overgassed---thats for running foreign ammo in filthy rifles,,,,,yes there is a difference in parts-buy a quality gasblock(NO ADJ)and a non-fancy gas tube...higher quality metal gas tubes defeat the purpose,the gas tube is supposed to fail before other parts.CDNN gas tubes are fine...And like Paw said-if you use set screws dimple the barrel for them-in the PROPER location.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #18 ·
Well I ordered a new gas block and tube. Waiting for their arrival.

In the meantime, I decided to go ahead and remove the old block and tube. This is proving to be a difficult task!

The block doesn't want to budge at all. Both set screws are removed of course.
I can't get it to move toward the muzzle or the receiver, so I tried to convince it to rotate, no luck there either.

I removed the roll pin that holds the gas tube in place, but the tube does not want to move. The gas tube has some play in the receiver, but I can't get it out of the block.

Any tips would be appreciated.
Thanks
 

·
Super Moderator
Joined
·
42,021 Posts
Use a hammer and a brass punch. Put the punch on the gas block and smack the crap out of it with the hammer.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #20 ·
Haha ... Yeah I've been giving it some decent whacks, to no avail.

I also gave it a few shots of CLP, didn't seem to help. I just applied some more, gonna let it sit for a couple hours and revisit it later.
 
1 - 20 of 21 Posts
Top