Ar 15 issues, update from earlier this summer

[dellet]

What do the tracks indicate?

Leaks.

You can find them between the tube and gas block. Coming out from between the block and barrel. Sometimes instead of a perfect carbon ring around the port, you find more of a starburst. Out from under a loose gas key.

Here’s a pretty big leak but gives an idea

 

[SecondsCount]

Unload and pull the bolt carrier group. Plug one end of the barrel, usually the chamber end, and pump compressed air unto the other. Is there air flowing out of the gas tube?

You can pull the gas block and measure from the muzzle end of the block to the edge of the port on the block with a dial caliper. Then take the caliper and use it to measure from the edge of the port on the barrel. Draw a line on the barrel with a pencil. You can also draw lines to indicate the centerline.

 

[DDriller]

If the gas block is butted uo to the shoulder it will not work.

 

[john 800]

I did another disassembly and look over, gas port looked to be lined up according to the carbon, there was carbon in fron of the gas key on the inside of the receiver, but I am not sure if that is normal or what exactly that tells me. I am going totry the bolt carrier group from another rifle if they interchange unless I come up with a better idea in the mean time. Other than inside the receiver I did not see any indication of a leak, checked everything that I could think of and everything mentioned unless I missed something.

 

[jelenko]

It's normal for there to be lots of carbon in the upper receiver.

You might check for gas leaks around the base of the gas key. The test is to put soapy water all round the base and blow compressed air into the key. If there's a leak, you'll see bubbles at the base of the key.

 

[Rsadams]

There is a gas tube in the gun correct..???? Seriously there's only a few things you need to have working on a DI gun.... Is there a gas port in the barrel..???? Is the gas black lined up with that port correctly.... If it's an adjustable gas block is it closed off if so open it up..??? You normally don't need to worry about a normal front sight assembly as long as it also is lined up with the port in the barrel correctly.... Does it have a or the right length gas tube installed , carbine , mid length or rifle length... If the bolt cycles manually and is working correctly it's working.. Is there a gas key on the bolt carrier..???? If so is it loose..??? If you install a BCG from another rifle and it still isn't working it's a gas problem reread above.... When you pulled it apart did the gas port in the barrel go all the way through to the inside of the barrel , it's not part drilled is it...???

 

[john 800]

Adiustable gas block....should be installed full closed. Then opened in 1/8 to 1/4 turn increments until it functions properly. Sounds like it may be full closed.

It is a standard gas block, secured with a set screw, not adjustable.

 

[john 800]

Ok, I think I finally have good news! I had checked the gas key and bolt carrier for leaks and didn’t find anything. What I missed was that there is only a tiny pin hole in the gas key letting gas in to the bolt. I saw it there but thought it was an engineered restriction untill I compared it to other rifles that are working, they have a much, much bigger passage. If I was a real “AR guy” It would have looked out of place immediately.
Guess I will look into some parts…
Thanks everyone! I appreciate the help

 

[jelenko]

tiny pin hole in the gas key

Where is this pin hole? I'm thinking it can't be easily visible since the gas tube has to go into the key quite a ways.

 

[Coyotefurharvester]

My 223 bcg(s) will fit a 3/32 Allan past the step down in the gas key, sorry didn't have a pin gage that fit. It's probably 1/8". Gas has to enter the bolt for the thrust required to unlock and cycle. There are gas bleeds on the side of the bcg.

 

[john 800]

Where is this pin hole? I'm thinking it can't be easily visible since the gas tube has to go into the key quite a ways.

If you look into the gas key from the gas tube sideit liiks like someone drilled down almost to where it curves then went from about a 3/16 bit down to th smallest drill bit you have ever seen, smaller than any carburetor jet I have ever worked with. Ill pst some pics if I can get one to show it.

 

[Konocti's Wigwam]

This sounds like a gas problem to me. I haven't seen what type of buffer the rifle has, or the length of the gas tube. Those may lead you to the problem.

 

[jelenko]

If you look into the gas key from the gas tube sideit liiks like someone drilled down almost to where it curves then went from about a 3/16 bit down to th smallest drill bit you have ever seen, smaller than any carburetor jet I have ever worked with. Ill pst some pics if I can get one to show it.

Well, that's not right.

As you've noticed, gas keys have no restrictions. If you have another bolt carrier you could just use that to confirm there's no other issues.

Where did you get the bolt carrier with this gas key from? They should make it right.

 

[john 800]

Where did you get the bolt carrier with this gas key from? They should make it right.

It is a midway AR Stoner upper, from what I have heard they are built by bear creek arsonel. When I bought them there wanst much feedback I could find good or bad because they were new. Now that I have learned about more people’s experiences, in addition to mine I don’t even want their parts in my gun, if it gets replaced it will get replaced with a quality part, as have both barrels. I never intended to “build” anything, like I said earlier I am not an ar guy, I just expected a couple factory assembled uppers to work and it has been a train wreck of an educational journey. I might as well build one now, I could put one together in my sleep after this BS

 

[jelenko]

bear creek arsonel

don’t even want their parts in my gun

Yep.