JP Silent Spring Short Stroking Question

Moderators: gds, bakerjw, renegade

Post Reply
BhamAR
New Member
Posts: 2
Joined: Sat Jul 02, 2022 7:02 pm

JP Silent Spring Short Stroking Question

Post by BhamAR »

I have a Thunder Ranch receiver set build with a Ballistic Advantage 10.3” barrel and an Aero Nickel Boron Bolt.

The bolt won’t lock back on a one round ammo test.

Now, I should point out, I’m using subsonic ammo and no suppressor. The reason is simply for safety on over penetration. This is for my dad who doesn’t have a suppressor. I think it would fully cycle with a suppressor on it.

The 300 subsonic gives him knockdown power inside his house without as much worry if he misses his target.

I know I can run a lighter JP spring to try and make it run. But can I also remove one of the three weights it comes with? They don’t have lighter weights for the JP silent spring, but I’m wondering if I can if I can run it with just two of the three weights.

Ejection pattern was 4:30-5 o’clock.

I’ve seen some people say a heavier weight might give more time for the gas to build. However, that seems somewhat counter-intuitive though I understand the premise.

So just wanted to see if anyone else had any experience with this.

Thank you.
User avatar
dellet
Silent But Deadly
Posts: 6967
Joined: Fri Nov 30, 2012 1:25 pm

Re: JP Silent Spring Short Stroking Question

Post by dellet »

Without knowing the ammo or load data it’s hard to help. Gas tube length and port size can also make a huge difference. jP does make two different weights, steel and tungsten. They also make a spring kit that has five different weight springs.

For diagnostics, it should have a standard carbine spring and an H2 buffer. This is how it was designed to work. That would not be a bad idea to start there and make sure they system is working properly, and or the load is workable.

Adding weight would be a complete mistake. The longer the bolt stays closed, the less pressure you will have to cycle the action.

If you can hold the weights in place with only two, it should work, as long as there is enough mass weight to keep the action from cycling too fast.

You should also try some supers to confirm the system can actually function.
300 Blackout, not just for sub-sonics.
BhamAR
New Member
Posts: 2
Joined: Sat Jul 02, 2022 7:02 pm

Re: JP Silent Spring Short Stroking Question

Post by BhamAR »

Pistol length gas

S&B 220 grain subsonic ammo.

Pinned gas block from the factory.

I may grab some supers and send them through, to check function, & help break in the system and spring.

I have two of them built identically, mine will have a suppressor on it, pretty sure it will be fine, but also wouldn’t cycle yesterday without the suppressor. Hadn’t had a chance throw my alignment rod down the barrel to insure safe suppressor shooting.

It’s pretty close, trigger resets, just doesn’t lock open or grab the next round.
User avatar
dellet
Silent But Deadly
Posts: 6967
Joined: Fri Nov 30, 2012 1:25 pm

Re: JP Silent Spring Short Stroking Question

Post by dellet »

If you can find it, try some Remington.

Also cycle the action to break it in, either by round count or hand at least 100 times.

Make sure it’s well lubed, if it’s not throwing oil in your face, it’s not enough until it’s broke in.
300 Blackout, not just for sub-sonics.
BJK
Silent But Deadly
Posts: 355
Joined: Thu Jun 18, 2020 8:30 am

Re: JP Silent Spring Short Stroking Question

Post by BJK »

How many turns on the spring? There are 2 lengths, one for a rifle buffer tube and one for a handgun. I know 'cause I made that mistake. Then I not only got the right length spring but also a flat wire spring to make sure I had enough space for it when compressed.

Sorry, I don't remember the number of turns for each. It should be easy to find though.

While I was waiting for the correct spring I clipped the overly long one and used it.
Post Reply

Who is online

Users browsing this forum: No registered users and 29 guests