10.5" AR pistol w\ midlength gas

[gr86ss]

I just finished putting together a 10.5" midlength gas system AR pistol. I'm getting some FTF problems. What would you recommend that I do to tune the timing??

thanks in advance

[Nathan Krynn]

buffer weight?

[h0use]

lube it up. are you using a pistol buffer tube with the right weight. i had the same problem with mine. i am using the spikes pistol buffer tube kit and it works fine now.

[Nathan Krynn]

Doesn't help you but both my 10.5's are carbine gas.

[gun toting monkeyboy]

Yeah. The most likely cause is that you have a gas system that is too long for the barrel. Monkey around with the buffer weight or spring. Try to decrease the resistance that your gas system has to fight. You are working with less gas pressure than you need to cycle the action. Your other option is to take it to a smith and have them open up the gas hole on your barrel to up the amount of gasses vented into the system, like they do on disipator carbines. Mid-length is wonderful for carbines. Not so much for pistols.

-Mb

[tomd1584]

Curious as to why you went midlength for such short of a barrel. Typically, carbine gas system is the choice for 7.5"-12.5" barrels. Especially if you're going with something from DD, BCM, Colt, or Noveske- as they have their gas port sizes dialed in.

[gr86ss]

Just ran home to check the buffer, it's a standard buffer that came on the PWS pistol lower. The barrel is a custom cutdown midlength gas barrel. The previous owner said that it worked fine on his set up, but I don't know what other components he used on his build. He said that the longer gas tube length helped buffer felt recoil on his build.

[gun toting monkeyboy]

Did you just get the barrel from him? Or did you get the upper from him? And he may say it worked for him, but you have no real way of knowing for sure. As for what he says about the longer gas tube, take that with a grain of salt. Not firing because of a FTF would definately have less felt recoil than actually shooting a round... I hope you can get it working, but realize that you may end up having to either take it in to get it fixed, or replace the barrel with one that has a regular carbine-length gas system. You might also give Randall at AR15Barrels.com a call. He is very good with these kinds of things.

-Mb

[MrPlink]

never heard of a middy 10.5. Interesting.

[Agent Tikki]

JP LMOS carrier, and a lightest spring and buffer you can find...........

Also a Noveske KX3 would definitely help you.

[gr86ss]

never heard of a middy 10.5. Interesting.

It's a custom cut barrel.

JP LMOS carrier, and a lightest spring and buffer you can find...........

Also a Noveske KX3 would definitely help you.

I'm using a Troy Claymore on the end

[gr86ss]

You might also give Randall at AR15Barrels.com a call. He is very good with these kinds of things.

-Mb

I have sent email to Randall. thanks for the recommendation

[HK35]

never heard of a middy 10.5. Interesting.

Yah, there's good reason why: not enough dwell time to cycle the action correctly.

[FeuerFrei]

Too long gas tube system without enough space between the muzzle and gas port.
Timing this will be a PITA.
Gas port size/location, length of gas tube and buffer weight will play havoc with your dwell time etc.. Barrel profile will affect gas port size choices too.
KX3 will help push up back pressure and use full power ammo might help.
You may end up with a picky eater.
Good luck.

[gr86ss]

Too long gas tube system without enough space between the muzzle and gas port.
Timing this will be a PITA.
Gas port size/location, length of gas tube and buffer weight will play havoc with your dwell time etc.. Barrel profile will affect gas port size choices too.
KX3 will help push up back pressure and use full power ammo might help.
You may end up with a picky eater.
Good luck.

I was hoping not to read a post like yours.. I have an email to Randall at AR15barrels.com and awaiting a response to see if he can salvage this barrel and make it work. If not, I guess that I will be purchasing another barrel...