What's wrong with the one ya got? what's not functioning that you think would function better? If it's too loud and chattery, smear half a teaspoon of red and tacky #2 on the spring. It's filthy and stinky stuff but it will silence the action completely for about a dime instead of $100. If the recoil is too violent then the gas system is where I would start, not the spring and buffer. We use normal springs in just about everything because they work good. If jp was reinventing the wheel with their captive piston spring thingy mo bobber we would see them everywhere. I just don't trust em or the kyn-shot for that matter.
