Looking for Baseline: JP Silent Captured Spring weight & Syrac Adjustable Gas Block

[Jagorrell84]

How's it going everyone? So tomorrow I plan on hitting the range for a few hours to take the first shots from my new build. I'm hoping to get a good starting baseline hopefully from so.eine who has the same setup as I do.

I have a JP Silent Captured Spring System with all the springs and a Syrac Adjustable Gas Block on it. What would be the ideal spring to start with of them all and as for the gas block, how far put should I have the set screw to start with?

Setup is:
20" 1:9 Twist BHW Fluted SS Barrel w/ JP Brake
Rifle Length Gas system with Syrac Adjustable Gas Block
Magpul UBR Stock (No JP SCS Spacer)
123gn Hornady A-Max Factory Rounds

Any help would be greatly appreciated.

Adam

[Holyfather12]

I'm not sure about the springs because I have never used them. Hopefully someone else from the horde can steer you in the right direction. As for the gas block it is trial and error. Start with a turn and a half or so and shoot a single round out of a magazine. If it doesn't eject the shell or lock back on the empty magazine turn it out a little more. Do this until your slide locks back and I like to give it another quarter turn or so in case one load is a little light. Here is a good video on how to adjust the gas block. http://youtu.be/evnB_C3U-Uc

[newb]

I start with trying to undergas and then adjust out. 1/2 turn starting point. And watch your grouping as you adjust around while you are in proper gas operation range. I have noticed that if I tune my block down to minimize the gas needed for proper operation range my grouping opens up.

I have no chrono data to back this up, I am assuming that dumping less pressure to bolt actuation is keeping barrel pressure higher, thus bullet velocity higher, and causing things to not be in their sweet spot. It shoots sub-MOA, isn't in the over-gassed range, and I'm not set up to reload Grendel yet. So I just leave it for the time being. If you reload I supposed you could adjust gas block down for what you need and tweek your powder to get tighter grouping back.



Silent capture I went with the regular set up for my starting point. Works fine so I never messed with the other springs..... yet.

[Jagorrell84]

I'm not sure about the springs because I have never used them. Hopefully someone else from the horde can steer you in the right direction. As for the gas block it is trial and error. Start with a turn and a half or so and shoot a single round out of a magazine. If it doesn't eject the shell or lock back on the empty magazine turn it out a little more. Do this until your slide locks back and I like to give it another quarter turn or so in case one load is a little light. Here is a good video on how to adjust the gas block. http://youtu.be/evnB_C3U-Uc

Thank you for the input. I watched that video a few days ago as well and it definitly did help. I just wish I knew what spring is the stock spring for the JP SCS as the kit comes wth all springs but doesnt have one installed like the standard version does, so I am not sure which color to put on for the standard setup.

[Jagorrell84]

I start with trying to undergas and then adjust out. 1/2 turn starting point. And watch your grouping as you adjust around while you are in proper gas operation range. I have noticed that if I tune my block down to minimize the gas needed for proper operation range my grouping opens up.

I have no chrono data to back this up, I am assuming that dumping less pressure to bolt actuation is keeping barrel pressure higher, thus bullet velocity higher, and causing things to not be in their sweet spot. It shoots sub-MOA, isn't in the over-gassed range, and I'm not set up to reload Grendel yet. So I just leave it for the time being. If you reload I supposed you could adjust gas block down for what you need and tweek your powder to get tighter grouping back.



Silent capture I went with the regular set up for my starting point. Works fine so I never messed with the other springs..... yet.

Thanks for the help. I just wish I knew what spring is the stock spring for the JP SCS as the kit comes wth all springs but doesnt have one installed like the standard version does, so I am not sure which color to put on for the standard setup.

[A5BLASTER]

Jagor give me a text and I will send you a close up pic of the spring on mine maybe it will help you figure out the standard weight spring from the others in the kit. 318-214-8525.

As far as the gas block on my rifle I belive it was 5 clicks backed off from full closed when it would lock the bolt back on a empty mag I then added two more clicks to ensure proper cycling with diffrent loads. I run the syrac gasblock

[LRRPF52]

My suspicion is that the SCS comes set-up for a low-mass Bolt Carrier, so it is sprung pretty heavy.

Even on my ~18" MLGS with .076" port, I needed to drop down to the white spring to get lock back. MLGS with that barrel length and dwell time usually is gassed pretty hard, so I got the impression the factory spring was on the heavier end.

On a RLGS, you will have even less dwell, with much less port pressure, but a larger port. You will end up running the adjustable gas fully open if you are able to get lock back at all.

Get the spring pack and use the lighter weights if it doesn't lock back for you.

[A5BLASTER]

Lets us know how the range day goes tommorw bro.

[newb]

I have standard weights and I used the black spring. -the spring with a tad hint of black painted on one end.

[Jagorrell84]

My suspicion is that the SCS comes set-up for a low-mass Bolt Carrier, so it is sprung pretty heavy.

Even on my ~18" MLGS with .076" port, I needed to drop down to the white spring to get lock back. MLGS with that barrel length and dwell time usually is gassed pretty hard, so I got the impression the factory spring was on the heavier end.

On a RLGS, you will have even less dwell, with much less port pressure, but a larger port. You will end up running the adjustable gas fully open if you are able to get lock back at all.

Get the spring pack and use the lighter weights if it doesn't lock back for you.

I have three spring pack and started with the middle of the 5. About 9 turns out from closed and my bolt is locking back perfectly. 8 out and the bolt catches but not fully open. Think I found the sweet spot. Thank you.

[Jagorrell84]

Lets us know how the range day goes tommorw bro.

Range day went very well today. I didn't have too much time but did get the scope dialed, gas block dialed, and it cycling really well. I was just shooting off a front bag sincentives I wasn't going for perfect accuracy today. I'll get my rest out there in the next couple days and see how she groups up with Factory Ammo. I appreciate all the help big time.

[A5BLASTER]

Cool bro glad it went well for you and your rifle.

[wheelguner]

I have the JP Silent Captured Spring assy (std weight) in both of my Grendels. One is an AA Overwatch with a 24" barrel and A2 Stock and the other is an AA Lite Hunter with a 20" barrel and collapsible stock. Both are functioning fine using the original supplied spring. This is the black color coded spring and of the five springs they offer is first up from the lightest.

This is with Hornady 123gr AMAX and my hand loads using Hornady 98gr VMAX.

I attached the spec sheet from their site.