Cycling issue with my AR

[jeager361]

I recently completed my first AR build. I took it out to the range to try it out. I am hoping that someone will be able to point me in the right direction in order to resolve the issue that I have with the gun cycling rounds properly.

I can charge the gun and a round will chamber fine. After firing the round, the bolt will close completely, but it is not always picking up the next round out of the magazine and chambering it. I would say about 50%+ of the time it will not pick up the next round. I then have to pull the charging handle again and it will chamber the next round.


As I said, I am not sure exactly where the problem might be and I am hoping someone can give me some direction in which to start troubleshooting.

Thanks!

 

[magic man]

What magazines are you using?

 

[jeager361]

I had a couple of PMAG magazines and a couple of cheap "gun show" magazines. I had the same issue regardless of which I used. That was my first thought at the range. I made sure to really get them seated up in the lower receiver. I thought maybe there was issues with the spring/follower in the magazine, but since all of them gave me the same trouble I don't know if that was the case.

 

[Trigger Time]

Is your buffer stamped with an h?

 

[Trigger Time]

Its either most likely a gas issue or buffer issue

 

[vwoodrum11]

I'd think a gas issue.

 

[KDUBCR250]

Does it lock back after the last round is fired ?

 

[threedhuntr]

Does it lock back after the last round is fired ?

^^^^^ This. sounds like its short stroking ... not enough gas flow.

 

[Tc343]

^^^^^ This. sounds like its short stroking ... not enough gas flow.

This would be my guess also.

 

[mvician]

Short stroking, more info on your "build" is needed to confirm. What did you build? Did you put the upper together? Is the gasblock aligned correctly?

 

[Sainte]

Check for the spring under the seer block. It's the spring just above the trigger. Shaped in a triangle shape, goes into a small cut out groove. Seer locks in to it. It is called the "disconnector spring" bottom center of the following diagram.

High-resolution exploded view of AR-15?

 

[EricG]

Gas block not installed properly. Is your gas block riding up against the "ridge" on barrel? Move it forward, toward muzzle, a 16th of an inch. Then redo set screw.

 

[Sainte]

It could also be the gas block is on backwards. I seem to remember seeing a lo rise gas block that had the gas tube hole drilled all the way thru.

 

[mvician]

Well without the OP giving us any more info, we could guess until we turn blue..........

 

[Sainte]

Yup, I've been checking up on this thread from time to time to see if it was resolved.....still nada.

 

[mvician]

Yup, I've been checking up on this thread from time to time to see if it was resolved.....still nada.

Yep, and not to pick on the OP, but these types of threads are why I don't recommend building your first AR without some kind of good background knowledge.
Sure they a "easy" to build, "easy" to mod, but if you don't have the knowledge they are also "easy" to screw up and not know why. Without knowledge of the system it is hard to explain your problem to get the right answer.

I can charge the gun and a round will chamber fine. After firing the round, the bolt will close completely, but it is not always picking up the next round out of the magazine and chambering it. I would say about 50%+ of the time it will not pick up the next round. I then have to pull the charging handle again and it will chamber the next round.

This is a straight forward example of "short stroking". Short stroking is caused by a lack of gas.

OP says he completed his "first build".

Did he build the complete rifle? Did he just assemble the lower and buy a complete upper? Or did he put the upper together too?
Didn't give us enough info to really go on.

 

[mvician]

Short stroking

If the OP put the upper together and used a bolt on gasblock...was the barrel dimpled to locate the gasblock? If the barrel wasn't dimpled, did he put the gasblock on upside down so he could see through the set screw hole where to align the block front to rear and mark that on the barrel? Or if the barrel wasn't dimpled for location, did he just mount it up against the shoulder of the barrel? If so, there needs to be a gap, the gap is where the handguard cap would usually be. If it is up against the shoulder, part of the gas hole in the barrel is now blocked. Blocked hole = not enough gas = short stroking.

If everything at the gas hole / gasblock is ok, the gas tube is next, since he says it works some times, we'll say the tube is installed correctly. Next is the gaskey on the bolt carrier. Are the screws tight? Does the key wiggle around? If the key is loose, you will loose gas pressure which will cause short stroking.

If all of that checks out.......what stock/receiver extension are you running? Rifle or carbine? Do you have too heavy of a buffer or too strong of a recoil spring for your gas system?
What ammo are you running? Brass 5.56 or .223? Are you running low powered steel case ammo? Did you lube the bolt carrier enough or are you running it dry?

Too many variables.......the rifle is short stroking, but why?

 

[Sainte]

my first thought was the problem you solved for me on your site with the connector spring not being installed. (MY first build! CB0021 haha. thanks again for that help too!)

 

[jeager361]

Yep, and not to pick on the OP, but these types of threads are why I don't recommend building your first AR without some kind of good background knowledge.
Sure they a "easy" to build, "easy" to mod, but if you don't have the knowledge they are also "easy" to screw up and not know why. Without knowledge of the system it is hard to explain your problem to get the right answer.



This is a straight forward example of "short stroking". Short stroking is caused by a lack of gas.

OP says he completed his "first build".

Did he build the complete rifle? Did he just assemble the lower and buy a complete upper? Or did he put the upper together too?
Didn't give us enough info to really go on.

First of all, I appreciate all of the input. Sometimes life gets in the way and I just wasn't able to get back to this post to update more information! I appreciate your opinion buying vs. building. However, building one from the ground up is the best way to learn, in my opinion. I undertook this as hobby project as something to do to tinker with. I am certainly not an expert and went in with my eyes open fully expecting there to be issues that I was going to need help with. I am not afraid to ask for help when I need it. I am not a lifelong gun owner, but it is a hobby that I have picked up in the last several years and it is something that I enjoy the heck out of. I reached out here because overall, this community has been a great asset to me in helping with my general knowledge. It was never my intent to ask a dumb question and waste anyone's time.

All that being said, I built the lower completely by myself. I purchased the barrel at the Indy 1500 a while back. It had the flash hider and gas block already assembled. The flash hider was pinned, so I was unable to do anything to change the gas block out. Because of that, I had some issues finding a rail that would work with the barrel nut that was already on the barrel. So, I took it to a gun shop here in Fort Wayne and had them assemble the barrel, rail, and gas tube to the upper that I already had.

As far as the buffer is concerned, I believe that that one I purchased was stamped with an h1. But without taking it apart, I don't recall for sure.

Now, another thing to note, I did have issues with the first bolt carrier group that I bought. It was an AR Stoner carrier. It would not fit over the gas tube. The key on the carrier appeared to be out of alignment. I returned it and got another and it fits on better. So maybe it is an issue with the BCG. I will check that as suggested.

I am going to tear it apart when I get a chance (hopefully this weekend) and check on some of the suggestions that you guys have already provided. If I can't figure it out, then I will probably take it back into the shop to have them give it a look over.

Again, thanks again for the help.

 

[mvician]

One thing to check on the bolt carrier...remove the bolt from the carrier. With the bolt out and the charging handle out, put the carrier back into the upper about a quarter way while holding it level. Tip the upper so that the carrier falls forward of it's own weight. Does the key slide nicely over the gas tube?

Still I believe the problem is with the alignment of the gasblock.