JP silent capture spring "tuning" springs

[rjacobs]

All the parts sans barrel will be here today for my SPRish build.

I got a JP silent capture spring, low mass carrier and will be running a Syrac adjustable gas block to tune it all. Barrel will be 18" rifle gas.

Before I start tuning the gas block would it be beneficial to pick up one of the "spring" packs that JP sells for tuning the silent capture spring? Or is this not needed with the adjustable gas system?

Ive never messed with adjustable gas OR the silent capture spring setup before so I just want to have all the parts in hand(if I even need them that is) before I start tuning.

 

[ORD]

The buffer spring that comes pre-installed in the silent capture unit is more or less the "do-all" spring. It was purpose-built to function best with the widest array of ammo, and was more or less meant to be THE SPRING used in conjunction with an adjustable block to fine tune the rifle's operation. The only real purpose for the alternate springs is with rifles/carbines that: a) even with the gas tuned way down on the gas block are still cycling more violently than necessary, are experiencing more recoil that they should (subjective) or are otherwise still apparently "overgassed" as a rule in which a heavier spring may be warranted; or b) even with the gas turned way up on the gas block are still not cycling properly (short-stroking, etc.) or are failing to activate the bolt catch on the last round fired from the mag in which case a lighter spring may be warranted.

Before dropping money on a $40 spring kit, just get your rifle assembled and then tested/setup and see what you might need from there. In all likelihood, the adjustable block should be more than sufficient in combination with the pre-installed spring in the silent capture unit to get you where you want/need to be.

 

[DWood]

OP, may I ask why you are going with the JP spring system? I just built my own SPRish 18" rifle and I'm curious about your thought process for the Silent Spring.

I hope to get out next week to shoot mine; just waiting on the scope mount.

 

[rjacobs]

The buffer spring that comes pre-installed in the silent capture unit is more or less the "do-all" spring. It was purpose-built to function best with the widest array of ammo, and was more or less meant to be THE SPRING used in conjunction with an adjustable block to fine tune the rifle's operation. The only real purpose for the alternate springs is with rifles/carbines that: a) even with the gas tuned way down on the gas block are still cycling more violently than necessary, are experiencing more recoil that they should (subjective) or are otherwise still apparently "overgassed" as a rule in which a heavier spring may be warranted; or b) even with the gas turned way up on the gas block are still not cycling properly (short-stroking, etc.) or are failing to activate the bolt catch on the last round fired from the mag in which case a lighter spring may be warranted.

Before dropping money on a $40 spring kit, just get your rifle assembled and then tested/setup and see what you might need from there. In all likelihood, the adjustable block should be more than sufficient in combination with the pre-installed spring in the silent capture unit to get you where you want/need to be.

Thats what I was reading. Im sure I will be good to go. Im not worried about needing to tune for function vs. non function(which may be the case with a non adjustable gas gun). JP's site says the springs are really designed for non adjustable gas block guns. If anything I would maybe want a lighter spring to use in conjunction with the light weight carrier to be able to turn the gas down even more. That is more my thinking vs. needing a heavier spring.

OP, may I ask why you are going with the JP spring system? I just built my own SPRish 18" rifle and I'm curious about your thought process for the Silent Spring.

I hope to get out next week to shoot mine; just waiting on the scope mount.

I went with the low mass carrier and adjustable gas so figured why not go with the silent captured spring setup. I shot a guys gun(16" carbine gas I think) with just the silent captured spring and it was so smooth. Im hoping to tune for basically zero recoil.

The other part of me buying it is that I went with all high end parts on this build and I didnt want to skimp on anything. Not saying a regular spring and buffer is skimping, just wanted something a bit "nicer" I guess.

 

[DWood]

Thanks. let us know how it shoots.

 

[Regalkismet]

Since you are using a low mass carrier and an adjustable gas block the factory included spring should be perfect.... The factory spring is one of the lighter ones available... It's the 85 rate spring... If you were running a heavier bolt carrier a different spring may be of some advantage, under certain conditions, but in your case your set up should be perfect....If memory serves me right they come in rates of 80, 85, 90, 95, and 100... a lower spring rate (i.e., heavier spring) with a properly tuned gas system can often yield a faster, lighter impulse. Also you do not have to spend $40 on a whole spring kit as you can buy the springs individually if you know what rate you need... $12 apiece I think.

 

[rjacobs]

Good to know. Saves me some money!