AR15 Charging issues

[denimdan85]

Whenever I try to pull back on the charging handle it seems to stick at first coming out of battery. This started happening when I was taking CMCT's Intro to Tac Shooting class. During the day I had several Failure to Fire using Federal M855. After inspecting more when I got home I found that it is not going fully into battery every time even without a round (maybe a I am just not Costa'ing the charging handle well enough) so this may be why I was getting the failure to fires and I just did not realize it because I was getting so much information crammed into my head.

I have recently changed out the handguard and had to replace the barrel nut.So the gas tube and chopped A2 front sight were removed. Between that time and the class I took it up to Hap Baker and put 150 rounds through it with no issues. I did not have access to a torque wrench before I took it to the range so I torqued it to what I felt was between 30 and 50 ft lbs. I was later able to borrow a friends torque wrench and found the barrel nut was torqued to 35 ft lbs. Thinking I was being safe I torqued it down to 50 ft lbs before going to the class. The torque wrench was not the type that you dial the torque and it 'breaks' when that value is reached. It was an old one that appears to measure the torque by how much the handle bends so who knows how accurate it is.

I have taken the bcg apart and made sure everything was clean and lubed according to Clandestine's teachings.

What could be causing this? Any help is greatly appreciated.

 

[outrider58]

Pull your buffer and check your spring. Make sure it is ok. Measure length-rifle between 11.75''-13.5'' or carbine- 10.06''-11.25'' It's some place to start looking.

 

[outrider58]

Does the charger stick even on an empty chamber?

 

[iH8DemLibz]

Bent/misaligned gas tube.?

That little mushroomed area on the end of the tube may be hanging things up some inside the gas key.

 

[mopar92]

My bet would be a bent gas tube and or misaligned gas tube.

Also are you sure you where properly pushing the charging handle into battery each time?*

Any work done on the FCG?

You mentioned you removed the chopped A2 front sight. What type of gas block did you replace it with?


*sarcasm

 

[Sticky]

Strip the bcg down to a bare bolt carrier and try to just 'slide' it into the upper. Does it go all the way in easily without resistance?

If not, check your gas tube alignment as mentioned. You should see wear on the end of the gas tube somewhere from the interference with the gas key on the carrier.

 

[denimdan85]

I just broke it all down and checked what you all asked about. I pulled the gas tube and colored it with a sharpie where it interacts the the bcg and racked it a few times. It appears to be rubbing on the top of the gas tube (side closest to the top of the receiver). I pulled the gas tube back out and put the gun back together and racked it a few times and it moves freely like it should. So it must be the gas tube causing the issue.

Is it possible to put the gas tube in crooked? I am using a chopped a2 front sight gas block. It would make sense that since it is pinned the gas block will be aligned correctly and therefore it must be the tube that is actually bent a little. I guess I boogered it. Does this sound correct? If so then all I should need is a new gas tube?

Thanks again.

 

[mopar92]

Did you completely disassemble the gas system when you retorqued it? Its possible that when you reassembked the gun the barrel nut was just a skosh off so that the gas tube would enter but be off just a little bit.

 

[denimdan85]

Did you completely disassemble the gas system when you retorqued it? Its possible that when you reassembked the gun the barrel nut was just a skosh off so that the gas tube would enter but be off just a little bit.

It is a Midwest Industries rail so the barrel nut is not the stock barrel nut and does not have anything interfering with the gas tube like a stock barrel nut does. I retorqued it with the gas tube in place if I remember correctly. It appeared I had enough clearance but the more I think about it I must have bent the tube when I did it.

 

[outrider58]

Perform gas key-gas tube alignment test:

with the CLEARED receiver held vertically, muzzle pointing down and charging handle removed. Take your bolt carrier(with bolt removed) and let it free-fall down into the upper receiver. if it meets any resistance or fails to drop all the way into battery, then either your gas tube is misaligned/crooked or you may have an obstruction inside the gas key.

 

[lennyk]

Did you completely disassemble the gas system when you retorqued it? Its possible that when you reassembked the gun the barrel nut was just a skosh off so that the gas tube would enter but be off just a little bit.

Yep, and absolutely. That gas tube has to be clearly free and clear when it enters the upper. I typically install the barrel nut with the gas tube vertically and let the gas tube fall in when nut is aligned. Works very well.

 

[denimdan85]

Perform gas key-gas tube alignment test:

with the CLEARED receiver held vertically, muzzle pointing down and charging handle removed. Take your bolt carrier(with bolt removed) and let it free-fall down into the upper receiver. if it meets any resistance or fails to drop all the way into battery, then either your gas tube is misaligned/crooked or you may have an obstruction inside the gas key.

When the bolt is out it is a little smoother to pull back on the handle but it still will not drop fully without a tap on the FA. I don't see how the gas tube could be misaligned because it is a pinned gas block so there isn't any way it could be misaligned since the pins wouldn't go in. Maybe I am wrong? I am leaning towards it being caused by me bending the gas tube slightly when I torqued the barrel nut with the gas tube on. Which is possible because the barrel nut for this rail in no way interferes with the gas tube.

 

[denimdan85]

This is what the barrel nut looks like.

https://www.midwestindustriesinc.com/index.cfm?fuseaction=category.display&category_ID=2524

 

[outrider58]

When the bolt is out it is a little smoother to pull back on the handle but it still will not drop fully without a tap on the FA. I don't see how the gas tube could be misaligned because it is a pinned gas block so there isn't any way it could be misaligned since the pins wouldn't go in. Maybe I am wrong? I am leaning towards it being caused by me bending the gas tube slightly when I torqued the barrel nut with the gas tube on. Which is possible because the barrel nut for this rail in no way interferes with the gas tube.

If you think you may have bent the gas tube, this is more than likely to be the problem. You will have to figure out which way it is bent and with something to pry it with, straighten it back out. Look closely as you move the carrier against the end of the gas tube. See if the carrier pushes to tube in a certain direction(sometimes you can stick your finger in there while doing this and feel the gas tube move in a particular direction). You do need to fix this before you get uneven wear on the lip of the tube. If all else fails, buy a new tube and see if that works, but you should be able to bend this one manually.

 

[Sticky]

A gas tube bender would be quite easy to fabricate.. here is one..

http://www.m-guns.com/tool_new.php?product=gtb

 

[denimdan85]

The gas tube is definitely bent. I have been playing with it trying to get it bent back so it lines up but cannot get it perfect. Every time bend it either a different side of the tube rubs against the gas key. I am just going to order a new gas tube and will report back if that fixes the issue which I am 99% positive it will at this point.

Thanks for all your help.

 

[denimdan85]

Just changed out the gas tube and the issue is gone. It now goes in and out of battery smoothly.

 

[outrider58]

Just changed out the gas tube and the issue is gone. It now goes in and out of battery smoothly.

Thanks to sticky and Mopar.

 

[denimdan85]

Thanks to sticky and Mopar.

Yes, very much so.

 

[Sticky]

Glad you figured it out! That is what it sounded like, luckily an easy fix