The button at 12oclock is the one that takes the most punishment on a breakbarrel, I had mine quite snug & set the power to mid 10’s when I first put them on. 500 shots later, I was up to 16ftlb as the buttons wore in. When I stripped the gun & sold off the parts, the 12oclock button was doing zero to prevent metal on metal, has it had worn flush with the surrounding piston body material. This was delrin rod btw, drilled into the piston skirt.