I just put a lightweight bolt carrier in my 3 gun carbine.  It's already got an adjustable gas block and now I have a spring pack to adjust the JP SCS.

I'm wondering where to start tuning it for the most reliable cycling and least recoil.

Would you go less gas and less spring?

Yes.

But don't work on two variables at once.

Pick your spring and then adjust gas to make your tifke run with it.

If that won't work, go up one doring and try again... Repeat.

ETA: if you tune in the summer add one click to gas block setting for cold weather use.

Watching these two videos from JP should help.

Those are great!

Thanks guys

bendigo:  I suggest you start with the lightest spring, to avoid excessive forward speed of the bolt going into battery.  Then dial back the gas block and start to gradually increase the amount of gas until fresh cartridges reliably feed, fire and eject to the preferred 3 to 4 oclock pattern.  If this isn't achieved readily, then incrementally increase the strength of the spring and start again.  Not sure what JP advises, but my ultralight 6.8 rifle has a reduced power spring from Taccom to keep the BCG's return speed within spec and avoid any bounce. - CW

I tested it last weekend.  Went with the lightest spring and dialed the gas block back 2 clicks.

XM193 ejected out at 3 oclock and tula ejected out to 4 oclock.

Very happy with the results.  Rifle is fairly lightweight but the crosshairs move about a foot at 100yards.