Earlier this summer I posted about a few ars I was having issues with. A new barrel fixed one. The second one was not feeding at all and would lock up and I had to drive the bolt back with a peice of wood to extract every round. At the time I dropped a round in the chamber by hand and it would not drop in without being pushed and once in it would not come out without being pushed with a cleaning rod. I ordered an x caliber barrel (18” with a mid length gas system) and today I tried it with the new barrel with several kinds of ammo. It still will not eject a round, at all. It will cycle by hand now where it would not before. I have been over the bolt amd bolt carrier group and gas system and I don’t see any issues, but I am NOT very familiar with ars or gas guns in general. Any thoughts?
Ar 15 issues, update from earlier this summer
- Thread starter john 800
- Start date
Highpower-FClass
Gold $$ Contributor
What do you mean by this? Does the gun go bang but the empty shell is not ejecting? Or something else?
The gun fires, the empty case stays in the chamber. I can cycle the bolt by hand and it ejects and feeds the next round properly.
I was at the range alone so I did not have someone to watch the bolt to see if it moved at all, I am not sure if it is partially cycling or not
Highpower-FClass
Gold $$ Contributor
If the gun fires and allows for easy cycling of the empty shell by hand there is a good chance the issue has to do with the gas system.
I would double-check that the gas block is perfectly lined up with the gas port in the barrel. If it is, I would try replacing the gas system components, starting with the gas block. Unusual as it is, I did have an occurrence of a faulty gas block leading to short stroking in the past.
The fact that your bolt does not move at all, or if it does move, not enough to eject the fired round, indicates that very little gas is being fed back into the receiver
I would double-check that the gas block is perfectly lined up with the gas port in the barrel. If it is, I would try replacing the gas system components, starting with the gas block. Unusual as it is, I did have an occurrence of a faulty gas block leading to short stroking in the past.
The fact that your bolt does not move at all, or if it does move, not enough to eject the fired round, indicates that very little gas is being fed back into the receiver
I am honestly considering replacing the whole gas system from block to bolt carrier group, at this point I wish I would have just bought a bolt gun. I got it for my daughter to huntbwith and have spent the whole summer trying to get the POS to function when we could have been spending time and burning ammo with practice rathe rthan trouble shooting something that was built flawed from day one.
No, but I did consider that when installing the gas block on the new barrel. It seemed right at the time, but I can certainly double check the hole m the gas block is above th ehole in the barrel
Make sure the gas tube is installed correctly also.
Aside from being lined up and right side up is there anything else I should look for?
I had suspected the gas tube to key fit but not sure what is normal or how to verify anything is right
Ar15s are simple lego sets. Ive assembled a couple dozen and have only ran into a few problems. Could you tell us what parts you have? Brand of upper, bcg, gas block, lower, trigger etc. Is the gas block a clamp style or set screw style or is it pinned on? Etc. Im sure we can help you get it running.
It was a midway ar stoner upper that didn’t work from new and their customer service was no help. It is all ar stoner parts aside from the xcaliber barrel I just installed. The lower works correctly with another upper I have so I dont think that is the issue. Buffer is standard at 2.9 oz and a carbine spring.
The bolt says MPI on it. It is a mid length gas system with a set screw style gas block.
I have a set of go/no go gauges and they go and dont as they should.
Coyotefurharvester
Silver $$ Contributor
I thought everyone blew through the gas tube after installing block/tube on barrel.
Adiustable gas block....should be installed full closed. Then opened in 1/8 to 1/4 turn increments until it functions properly. Sounds like it may be full closed.
If the bolt isnt moving at all thats a considerable gas leak or no gas at all. Being a set screw style block is there a dimple in the bottom of the barrel for the set screw? I ask because manufacturers dont always put the dimple there for where other manufacturers blocks will line up correctly. Do you have another carrier to try? I have seen the front gas key bolt break, creating a leak and inhibit proper cycling or any cycling. You cant see that its broken until you remove the bolt and only the head comes off. If very little use then its probably not likely. But there arent many things that would cause it not to cycle. If you just tightened down your gas block set screw into a dimple it might not be aligned right.
My Superlative one says open to full gas then adjust. At least that's my understanding. They SA doesn't recommend their gas block be fired when closed all the way.
Highpower-FClass
Gold $$ Contributor
It is possible to install the gas tube upside down in the gas block. If done, the hole in the gas tube will be facing up, allowing no gas to enter the tube.
If done so the gas tube angle would be awkward in that the bend would be facing down rather than up and it would be difficult to feed the tube through to the receiver.
Nevertheless one more thing you can check
dellet
Gold $$ Contributor
Start with the basics.
You say you’re not sure if the bolt is even moving. Confirm that. 100 psi air from a compressor will confirm whether the bolt will unlock. Just use a rubber tip nozzle blow it down the muzzle with the upper off or at least open. No spring pressure from the buffer.
Your gas block will have a set screw or hole of some sort on the bottom that will align with the gas port. They drill all the way through the block to connect the passage way where the gas tube goes into the block. Pull the set screw out, flip the block upside down on the barrel and align the port in the barrel with the set screw hole. That will tell you if the block needs to be pushed against the shoulder on the barrel or not. You mark the barrel for reference if you want and the. Just spin it 180.
Clamp on is basically the same. Just look between the ears.
It only takes a few rounds to leave a carbon mark around the gas port. Pay attention to that when you loosen the block. There should be a carbon circle with the gas port perfectly centered.
I have seen gas tubes and or blocks clogged with debris from the factory and barrels that have a burr that will shave the bullet jacket and clog the port or tube or key on the carrier.
Other things to look for are carbon tracks out from under the block.
Main thing is confirm if the bolt will unlock or not with air pressure, if it won’t, something is plugged.
Brake or carburetor cleaner blown through all the holes and tubes sure won’t hurt.
You say you’re not sure if the bolt is even moving. Confirm that. 100 psi air from a compressor will confirm whether the bolt will unlock. Just use a rubber tip nozzle blow it down the muzzle with the upper off or at least open. No spring pressure from the buffer.
Your gas block will have a set screw or hole of some sort on the bottom that will align with the gas port. They drill all the way through the block to connect the passage way where the gas tube goes into the block. Pull the set screw out, flip the block upside down on the barrel and align the port in the barrel with the set screw hole. That will tell you if the block needs to be pushed against the shoulder on the barrel or not. You mark the barrel for reference if you want and the. Just spin it 180.
Clamp on is basically the same. Just look between the ears.
It only takes a few rounds to leave a carbon mark around the gas port. Pay attention to that when you loosen the block. There should be a carbon circle with the gas port perfectly centered.
I have seen gas tubes and or blocks clogged with debris from the factory and barrels that have a burr that will shave the bullet jacket and clog the port or tube or key on the carrier.
Other things to look for are carbon tracks out from under the block.
Main thing is confirm if the bolt will unlock or not with air pressure, if it won’t, something is plugged.
Brake or carburetor cleaner blown through all the holes and tubes sure won’t hurt.
Easy test is use compressed air or basically any can (carb or brake cleaner) that has the red spray tube. Spray it in the gas tube and see if it comes out by the gas block. If a small or little amount comes out then it might be blocked or installed upside down.
What do the tracks indicate?
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