AR not chambering next round

thump_rrr said:
Check the end of the gas tube to ensure it isn't worn out.
Another thing to check when looking at the gas block is to see if there is a space between the end of the gas block and the barrel stop.
There should be a small gap of around 0.030". Typically the front set screw is in line with the hole in the gas block.
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I don't have a micrometer but yes there's a very, very small gap between the block and the barrel stop. Since I've now undone the set screws and moved the gas block to check things out, my concern now is making sure the block is lined up with the gas port when I set everything back.
 
Lots of god advice but I would also be sure to try better ammo before tearing into the rifle too far. Get some 5.56 spec ammo (55 or 62gr.) or some name brand .223 the same weight range and give that a try. I never start out shooting bottom of the barrel ammo when first shooting a new to me gun. Shoot quality stuff at first for function checks then step down in quality to find a reliable and cheap bulk ammo. Good luck to you , hope it doesn't turn into a big issue to fix.
 
Good easy instructions however the block should not touch the hand guard cap ridge or the gas port will be partially covered.
 
Good video, thanks! That's basically what I did and I'm back in business. I'll update this page next time I'm at the range with some different ammo and we'll see what happens..
 
If the screws are on the bottom of the gas block, the barrel needs to be dimpled for the screws to stay in place. If it's the kind that clamps (screws on the lower side) then they just need to be lined up and tight.
If it's aluminum throw it out and buy a steel one.
 
Hitzy said:
If the screws are on the bottom of the gas block, the barrel needs to be dimpled for the screws to stay in place. If it's the kind that clamps (screws on the lower side) then they just need to be lined up and tight.
If it's aluminum throw it out and buy a steel one.
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I'm not sure what kind of gas block it is, but it appears to be steel. The set screws are on the bottom and screw vertically against the bottom of the barrel, it's a solid unit that doesn't clamp.
 
Sqr said:
Good easy instructions however the block should not touch the hand guard cap ridge or the gas port will be partially covered.
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Depends on the gas block. Some have a slot or an enlarged hole (the ID of the hole in the gas block is usually the same size as the gas tube ID ~.110" iirc) so you can butt it against the shoulder or have it spaced away with the handguard cap
 
Travis Bickle said:
Check your gas rings on your bolt Sir.
Flick the bolt outward and try to stand the bolt up on its face on a table.
If the carrier can't stay up under its own weight without dropping/camming it's a good indicator that your gas seal rings on your bolt are shot. Easy fix.
Try that first and see if it fixes the problem.

If it's an allan key low pro gas block that is a common problem as well (that's why I don't use them, pins all the way!).
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Thats not the proper test as per the TDP. The proper way is to remove the firing and cam pin and hold the carrier with the bolt face down. The bolt should not fall out under its own weight. Many BCG with perfectly fine gas rings will fail the method you described.
:)
 
I also check it the same way that Malice described. Although I also test it the opposite way by holding the bolt and letting the carrier hang below. If it passes the first but fails the second, I know the rings are starting to get worn. Kinda like a half-life check.
 
*MALICE* said:
Depends on the gas block. Some have a slot or an enlarged hole (the ID of the hole in the gas block is usually the same size as the gas tube ID ~.110" iirc) so you can butt it against the shoulder or have it spaced away with the handguard cap
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True but all mil-spec blocks and barrels are manufactured to tolerances for the hand guard cap so why not install each one correctly with the gap in the first place? Eliminate all doubt first.
 
For those who are curious...

I ended up re-aligning the gas block. Then I gave the rifle a very thorough cleaning and ensured the proper points had lubrication. I checked the buffer/spring and gave it a very light oil as well. I bought some Hornady V-MAX to compare against my steel cased MFS stuff I was having issues with before. Took it to the range today and started out with a mag of MFS just to see, and it cycled all 5 rounds perfectly. Another mag of MFS, no issues. A LAR mag, no issues. I shot for about an hour and never even opened up the box of Hornady. Not sure whether the gas block was mis-aligned or maybe the rifle didn't have enough lube, but it seems to be chugging along just fine now! Thanks everyone for your suggestions. If I have issues in the future I'll report back here. Cheers!
 
CUSTOM441 said:
For those who are curious...

I ended up re-aligning the gas block. Then I gave the rifle a very thorough cleaning and ensured the proper points had lubrication. I checked the buffer/spring and gave it a very light oil as well. I bought some Hornady V-MAX to compare against my steel cased MFS stuff I was having issues with before. Took it to the range today and started out with a mag of MFS just to see, and it cycled all 5 rounds perfectly. Another mag of MFS, no issues. A LAR mag, no issues. I shot for about an hour and never even opened up the box of Hornady. Not sure whether the gas block was mis-aligned or maybe the rifle didn't have enough lube, but it seems to be chugging along just fine now! Thanks everyone for your suggestions. If I have issues in the future I'll report back here. Cheers!
Click to expand...

It was a gas issue, lack of lube will not cause issues this early after cleaning.
 
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