AR-15 cycling issues

[herman]

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[ott1]

Are you using a rifle buffer spring or a carbine buffer spring? You listed JP Rifle buffer spring but not what it actually is. With DI, you need the gas rings on the bolt.

[Gutz]

Are you using a rifle buffer spring or a carbine buffer spring? You listed JP Rifle buffer spring but not what it actually is. With DI, you need the gas rings on the bolt.

This...

My best guess is the DI system is failing somewhere and not properly pushing the bolt all the way back or the spring/buffer are binding up and and not allowing the BCG to go all the way back.

[herman]

Thanks for the catch..it's a carbine buffer spring. I put the gas rings back on the bolt. I also changed the hammer out it seemed to be dragging on the carrier a little too much.

Was also curious about a JP reduced power hammer spring? What do you think?

[buellster]

Sounds under-gased. Check gas block alignment or gas port size. So you put the rings back on the bolt before you test-fired it?

[FeuerFrei]

try a lighter buffer. carbine weight


Sent with 2 cans & a long string.

[ClintonJ]

Had a similar problem on an AR build. Short stroked every time. Turns out my gas block gas hole wasn't lined up with the barrel port hole. I figured they'd be lined up just because I pressed the gas block all the way onto the barrel. Not the case. I needed to back the gas block off the width of a few pieces of paper so the holes matched up fully. Good luck.

[herman]

Yes seems to be short stroking..
I replaced the McFarland gas ring for the normal gas rings when i got home from test firing.
Also changed buffer spring with a lighter one.
I'll check the gas block alignment later today when i get home.
How big should the gas hole be?
Thanks for all the help.

[GUNNTZ]

There is a range on the port size, it depends on the manufacturer and application. It really sounds like you don't have enough or any gas hitting the BCG. Block the chamber side of the barrel and put some air pressure on it if you can. You should be able to hear a decent amount of air coming out of the gas tube.

[ar15barrels]

Spike H2 buffer

Daniel Defense 18" CHF heavy barrel melonite coated mid-length gas port

Midlength barrels generally do NOT need heavy buffers.
Drop back to a standard weight carbine buffer and try that.
DD barrels have smaller gas ports that are best suited to standard carbine buffers.

[cgates]

my first thought as well. I would not have started with an H2 buffer on a mid-length system. As long as your gas port is properly lined up with the block, my bet would be the buffer change fixes the problem. lighter hammer/trigger springs wouldnt help you here.

[TeirHawg]

Sounds like you may have the problem narrowed down.

If not, do you have access to another functional AR? Swap uppers/lowers and see if you can find which is the "bad" half. I'd also recommend only changing one part at a time while you are trying to locate the issue.

Example: if you swap out three different parts and find it now works, which of the three was the problem? Swap one at a time makes is easier to find out.

[herman]

I do have another AR and tons of spare parts. The other AR is piston driven not DI. Not sure too many parts will interchange. I did change the buffer and spring I'm going to check the gas port alignment. I did notice it's easier pulling the charging handle after the spring change. Thanks for all the suggestions I'll try and test fire tomorrow or next day. Will keep you posted thanks

[herman]

Thanks for your help..it's cycling perfect now. Gas block was a hair to far forward.

[Gutz]

Thanks for your help..it's cycling perfect now. Gas block was a hair to far forward.

Awesome! How about a pic of the AR?