Gas system help.

[cookietheswede]

I have a .308 mega MA-TEN build that is short stroking and will not hold the bolt open after the last shot.

I Started with a paladin machine 2 position (suppressed/full open) gas block with a slash heavy buffer and AR 10 spring. Gas System is rifle length.

I have tried switching to a PRI adjustable gas block and went to a DPMS buffer and spring. Tried them all separately with no luck.

Barrel is from GAP, DPMS bolt carrier, PRS stock are other items in the system. Also have tried different rounds, FGMM 168 and 175gr and Southwest Ammo 175gr.

Any ideas before I send it to a smith?

 

[dlxcupid]

Re: Gas system help.

did you check your mags? will the bolt hold when cycling it manually?

 

[cookietheswede]

Re: Gas system help.

Yes, forgot to add that. Holds open fine with 3 different Magpul PMAG's manually.

 

[dlxcupid]

Re: Gas system help.

Did you use the Magpul screw for the stock? Some people use a regular stock screw and it's too long so the bolt won't go back all the way. Make sure your gas tube and gas port isn't clogged.

 

[cookietheswede]

Re: Gas system help.

I used the Magpul screw and cleaned up the gas port and blocks and no luck.
I am starting to think my gas port is to small. I have tried 3 different gas blocks with gas tubes, 2 different buffers and two different springs.

 

[slothlacrosse]

Re: Gas system help.

try an AR15 rifle length buffer spring.

i was having some timing/feeding issues with my AR10 and that seemed to have taken care of everything.

 

[FrozenRopes]

Re: Gas system help.

I had an issue with a new bushmaster AR-15, and it was caused by my lack of cleaning the chamber. I was so excited to shoot it. I didn't take the time to scrub the chamber and it short cycled 'til I gave it a good cleaning.
Probably not the solution but just an idea.

 

[Phylodog]

Re: Gas system help.

If you haven't done so check the carrier key to make sure it's tight and check the gas rings.

 

[9H_Cracka]

Re: Gas system help.

Use a set of pin gauges or number drills to measure the gas hole and report back that number.

What length barrel are you running, and has its length been modified since it left its maker?

 

[PLeighton]

Re: Gas system help.

This:
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Phylodog</div><div class="ubbcode-body">If you haven't done so check the carrier key to make sure it's tight and check the gas rings. </div></div>
and also,
- Check the gas block allignment.
- Check the gas tube to make sure it is not binding in the key.
Best way to check that is to take the bolt out of the BCG and slide the carrier in the upper reciever using your finger.
You will feel it if there is a binding issue.

How is the felt recoil?
Where is the brass landing in respect to the rifle? (2 O'clock, 3 O'clock, etc.)

 

[cookietheswede]

Re: Gas system help.

My job keeps getting in the way of me having a functioning rifle. Had some time to check things out today.

All parts are new and were properly cleaned and lubed. Also there is no sign of excessive wear. I have only shot 168 rounds through it.

_9H
Gas port is a #42 hole.
Barrel is 18" long.
Gas port is 5 3/4 from end of barrel.

Dr. Phil
Recoil is very manageable could shoot all day.
Brass is ejecting around the 4 O'clock position about 5' away. There is a few marks on the deflector where the forward assist would be.

Thanks for the help