JP Adj. Gas Block

[wnroscoe]

This is kinda weird as you'll see.

A few months ago I shortened and threaded my LR308 barrel from 24" to 20". With / without my Gemtech Sandstorm it ran fine. I just installed a .936 bore adjustable JP Gas Block on the rifle, installed the suppressor and attempted to adjust it per the instructions. No dice, no lock back after single feeding it. The set screw ended up being out so far that it eventually shot out of the gas block and wha-lla, the rifle cycled fine again, locking the bolt back after single feeding it

I installed a new, short set screw to just seal the hole off and again, no love from the rifle, it failed to lock back after single feeding. I re-installed the original gas block on the rifle and I'll run it again tomorrow but, I thought this was very strange, almost like the new block was over gassing even more until the set screw came out.


Whatcha think??

 

[SSSamurai]

Re: JP Adj. Gas Block

I'm totally guessing, but your last statement sounds like the only logical explanation. It is so overgassed that it's overrunning the bolt catch before it can lock open. Did you try screwing the adjustment screw all the way in? I am guessing this because you say it locked back when the screw was out, which should mean it was dumping a lot of gas out of the system.

 

[wnroscoe]

Re: JP Adj. Gas Block

Started with two turns out from all the way in. I'll have to get another set screw as mine's now AWOL but, will try all the way in minus one turn or so, that does make since.

 

[KYS]

Re: JP Adj. Gas Block

I would wait for the Noveske Switchblock to come out.... just sayin'

 

[wnroscoe]

Re: JP Adj. Gas Block

1/4 turn out from all the way in did the trick. Runs like a top now suppressed. The LR308's must really be over gassed with a gas port of .093" and a standard gas block. The JP single stage adjustable trigger is also money, easy to install, great end result.

 

[dieselten]

Re: JP Adj. Gas Block

my LR308 had a very light buffer and a very weak action spring, I read that this was the case with all LR308's. I replaced buffer with x heavy from Slash and replaced action spring with factory Armalite AR10. The spring is so heavy it takes 2 men and a boy to charge the rifle. This was like giving penicillin to my rifle, it made it work perfectly with and without can.

 

[wnroscoe]

Re: JP Adj. Gas Block

The rifle ran fine at 24" and then at 20". The issue was the blow back when suppressed. I felt it was way over gassed and wanted to correct it. The buffer in this rifle is fairly heavy and has a buffer spring to match. Shot it again today and it runs great, no blow back and very smooth feeling on recoil. The factory A2 stock is next on the list to take a hike.

 

[MikeeBooshay]

Re: JP Adj. Gas Block

Glad to hear and learn from this.

I have a partially finished 6.5CM, WAY overgassed, even unsuppressed. W/can, it's silly, rips the bolt stop/catch off the mag ( was an AR10T before ).

I was trying to decide which adjustable gas block to use, the thread didn't help much with that, but reminded me toget something ordered this week. Been busy with a couple other projects, getting ready for duck season and such.

 

[Hoser]

Re: JP Adj. Gas Block

I am using PRI adjustable gas blocks. The JP ones are good also, but I have had better luck with the PRI.

 

[Hellbender]

Re: JP Adj. Gas Block

Don't trust locktite on on the threads of that little setscrew, gets way too hot.

http://www.snipershide.com/forum/ubbthre...921#Post1973921

 

[Longshot38]

Re: JP Adj. Gas Block

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wnroscoe</div><div class="ubbcode-body">1/4 turn out from all the way in did the trick. Runs like a top now suppressed. The LR308's must really be over gassed with a gas port of .093" and a standard gas block. The JP single stage adjustable trigger is also money, easy to install, great end result. </div></div>

I agree the LR308 are REALLY over gassed. I have my gas block setup the same way unsuppressed. Out of curiosity do you have a comparision between the JP trigger kit and just the spring replacement. I just installed the JP spring on a mil spec trigger and it does well. But I have never tried the entire JP trigger kit.

 

[mbandy13]

Re: JP Adj. Gas Block

I love the JP trigger, but I find when you put them in an AR-10 the spring just doesnt have enough pop on it to make the primers go reliably. Just personal experience.

mike

 

[SSSamurai]

Re: JP Adj. Gas Block

I have been waiting for a 7.62 Switchblock for years....

 

[3O8Junkie]

Re: JP Adj. Gas Block

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SSSamurai</div><div class="ubbcode-body">I have been waiting for a 7.62 Switchblock for years.... </div></div>
+1

 

[smokshwn]

Re: JP Adj. Gas Block

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: mbandy13</div><div class="ubbcode-body">I love the JP trigger, but I find when you put them in an AR-10 the spring just doesnt have enough pop on it to make the primers go reliably. Just personal experience.

mike </div></div>

In all of JP's literature they recommend the red springs when installing the trigger in a 308 platform gun.

 

[uscbigdawg]

Re: JP Adj. Gas Block

Use either JP's red springs or stock springs in a 308.

Mr. Roscoe - Glad you got it worked out and yeah...the LR308's are WAAAAY over gassed.

Rich