Ar15 gas issue

[inline 6]

I'm putting together an upper with some new parts. I installed the gas tube on the gas block and then slid it down to its gas block seat but did not tighten it down yet. When I install the bcg the gas tube bottoms out inside of the gas key and the only way the bcg will lock is to push the gas tube and block off of its seat a bit.

Any ideas?

[Blackpony]

Gas tube too long?

[Gargamel]

Are all of these parts new?

Couple of possibilities here assuming the upper receiver is within spec.

1. The gas tube area within the gas block is not within spec (too shallow)
(Make sure that the gas tube hole lines up with the hole in the gas block)

2. The gas tube is out of spec. Too long.

3. The gas key is out of spec or improperly staked

[Gargamel]

System Barrel Length Port Distance
Pistol Less than 10 inches 4 inches
Carbine 10-18 inches 7 inches
Mid 14-20 inches 9 inches
Rifle 20 plus inches 12 inches

https://www.at3tactical.com/blogs/news/9298047-carbine-mid-or-rifle-a-beginner-s-guide-to-ar15-gas-systems

[inline 6]

The only new parts are the barrel and the gas tube. All other parts were together and functioning before I changed out those 2 items. So either the barrel is not right or the gas tube isn't is what I am gathering.

[Gargamel]

The only new parts are the barrel and the gas tube. All other parts were together and functioning before I changed out those 2 items. So either the barrel is not right or the gas tube isn't is what I am gathering.

I would agree with your analysis....

[NoClassic]

Do the barrel and block ports align even with the gap?

[inline 6]

Do the barrel and block ports align even with the gap?

No, I eyeballed that first and it needs to be on the seat to be right.

My gas tube is 9.783" long

The barrel is 7.037" form the barrel nut seat to the center of the gas hole

I'm thinking of tweaking the gas tube a bit to shorten it up.

[Gargamel]

No, I eyeballed that first and it needs to be on the seat to be right.

My gas tube is 9.783" long

The barrel is 7.037" form the barrel nut seat to the center of the gas hole

I'm thinking of tweaking the gas tube a bit to shorten it up.

that's the problem... as it seems to be too long.

[inline 6]

I think this is carbine length? It's an 11.5" voodoo barrel from adams arms.

Sent from my SM-N920T using Tapatalk

[Gargamel]

From the measurements and the type of barrel, it looks like you have the right parts.

Be damn sure that the gas tube is all the way in the gas block and that the gas holes in the gas block and tube fully line up.

Other than that, I would just shorten the gas tube a bit and call it a day.

Measure twice, measure one more time, mark, cut, square the end, deburr the inside and outside edges, blow out chips with compressed air, install.

[KBScobravert]

check that the gas tube doesn't need to go in from the other side of the gas block. Some are open on both ends and that one doesn't look like it is shaped to tell you otherwise...from the picture.

check the gas block and make sure that the hole is going to sit over the hole in the barrel. I measure the center of the gas port in the block to the face and then from the barrel's shelf and the center of the gas port. A little bit of math and I get a gap measurement that I need to have a centered block/port.

If all the above is correct, and the BCG will still not go all the way forward, I would take the gas tube out and take a little a time off until the BCG seats in the forward position...like mentioned in posts above.

[inline 6]

check that the gas tube doesn't need to go in from the other side of the gas block. Some are open on both ends and that one doesn't look like it is shaped to tell you otherwise...from the picture.

check the gas block and make sure that the hole is going to sit over the hole in the barrel. I measure the center of the gas port in the block to the face and then from the barrel's shelf and the center of the gas port. A little bit of math and I get a gap measurement that I need to have a centered block/port.

If all the above is correct, and the BCG will still not go all the way forward, I would take the gas tube out and take a little a time off until the BCG seats in the forward position...like mentioned in posts above.

Its an adjustable gas block so I can only put it in form one end. I send adams arms an email as the gas tube came from there and they are sending me a new one. I just don't want to fuck with it and I'm in no hurry. Shit like this should fit right the first time. This was supposed to be one of their VDI nice gas tubes. I know its a gas tube but the fucker was near $40 shipped. After removing some of my others for cleaning and seeing them eroded away around the gas hole from what I assume is excessive heat from full auto I wanted something that might hold up a tad bit better.

[Gargamel]

Damn... $40 for a gas tube?

cha-ching!

[inline 6]

Damn... $40 for a gas tube?

cha-ching!

With the freight ya, I was surprised myself. It looks nice tho!