Custom AR Rifle cycling problems

[Pariah3j]

Took my AR15 out to the range this weekend. Its a custom build using a internal DPMS parts kit. It has been a great gun, shoots good - at least until this weekend. I was having to manually charge the charging handle after every shot to eject the spent brass and load the next round. I had a mix of different ammo and tried 2-3 different mags. So the problem would appear to be the rifle itself. This is a new one for me, never had this problem with an AR before. Just looking for some thoughs/feedback as to what I should check/try to resolve the issue ? I haven't had a chance since the range to break the gun down and clean/inspect it. I'll take some pics and post it when I do.

[psijac]

Did the gas block come loose?

[Pariah3j]

Did the gas block come loose?

I wouldn't think so, but anything is possible. I will check that this evening when I break the gun down and clean it.

[Pawpaw]

Did the gas block come loose?

Its more likely the gas tube came loose or got crushed.

Back in the day, we were taught to smash the top of the handguard against something hard to disable an M-16 to prevent the enemy from using it against you. It worked well with the old triangular handguards.

[Bitter Clinger]

Took my AR15 out to the range this weekend. Its a custom build using a internal DPMS parts kit. It has been a great gun, shoots good - at least until this weekend. I was having to manually charge the charging handle after every shot to eject the spent brass and load the next round. I had a mix of different ammo and tried 2-3 different mags. So the problem would appear to be the rifle itself. This is a new one for me, never had this problem with an AR before. Just looking for some thoughs/feedback as to what I should check/try to resolve the issue ? I haven't had a chance since the range to break the gun down and clean/inspect it. I'll take some pics and post it when I do.

Also, take bolt apart and make sure ejector recess, ejector slot & bolt face are clean of brass shavings. Clogged ejectors are often responsible for fail-to-ejects. Check to make sure that extractor spring and plunger assembly is intact and functioning as well.

[Pariah3j]

Did the gas block come loose?

Its more likely the gas tube came loose or got crushed.

Back in the day, we were taught to smash the top of the handguard against something hard to disable an M-16 to prevent the enemy from using it against you. It worked well with the old triangular handguards.

No crushed gas tube - handrail won't allow it... Can't really get to it but the piece of the tube in chamber doesn't move

Also, take bolt apart and make sure ejector recess, ejector slot & bolt face are clean of brass shavings. Clogged ejectors are often responsible for fail-to-ejects. Check to make sure that extractor spring and plunger assembly is intact and functioning as well.

Everything looks fine, no shavings and bolt appears to be functional


Went ahead and gave it a good cleaning- My wife said she believes I didn't clean it after the last range visit before this weekend. I usually clean all my guns the day of or day after the range. But the last time I went was on a busy weekend and I can't remember if I cleaned it. Plus its been in the trunk of the car for the last couple weeks, thinking back I'm not sure how well oiled it was this weekend. Gonna give it another try hopefully this weekend and report back. At this point I'm just hoping its a typical finicky AR15 issue.

[Pariah3j]

Gas-key isn't coming loose?

I would have said no but I went back and it was loose... Tightened it back down... Didn't seem that loose but there was some noticeable give ...

[maverick2076]

Check the rings on the bolt and make sure that the gaps in them are offset from each other as well and not all lined up.

[remington79]

Now that you tightened it you need to stake it. http://www.m4carbine.net/showthread.php ... omparison)

http://www.m4carbine.net/showthread.php ... se-Threads

[DocV]

Now that you tightened it you need to stake it. http://www.m4carbine.net/showthread.php ... omparison)

http://www.m4carbine.net/showthread.php ... se-Threads

MOACKS if you can get your hands on one. Otherwise a punch.

[Rrash]

I had a similar situation with a custom AR. It turned out that when I changed the endplate (so I could add a QD sling), I reinstalled the buffer tube one turn too short, causing the bolt to travel just a hair too far back. Once I tightened it one more turn, I haven't had any issues since.

That may or may not help, but a good reminder that you will become a seasoned trouble shooter when you build your own.

[Pariah3j]

I had a similar situation with a custom AR. It turned out that when I changed the endplate (so I could add a QD sling), I reinstalled the buffer tube one turn too short, causing the bolt to travel just a hair too far back. Once I tightened it one more turn, I haven't had any issues since.

That may or may not help, but a good reminder that you will become a seasoned trouble shooter when you build your own.

Good to note Rrash - I'll take a look at that and double check

Now that you tightened it you need to stake it. http://www.m4carbine.net/showthread.php ... omparison)

http://www.m4carbine.net/showthread.php ... se-Threads

MOACKS if you can get your hands on one. Otherwise a punch.

Does it need to be done again if it was already done ? It obviously didn't stick but didn't know if it would help to re-stake it.

[remington79]

You should if it didn't stick. It needs to look like the first set of photos. The sides of the nut should be deformed so that there is no way that it can be unscrewed or otherwise loosen up. Make it so yours looks like the pictures of the Colt or BCM carrier. You should also check the castle nut to make sure it's staked to.

[DocV]

Before you stake be certain you torque the key screws to 35-40 inch pounds. Then each screw in three places. You will need to fire three to eight rounds after staking to seal the key. You may have to manually charge until the key is sealed.