You are going to have to change the springs and (maybe the valve) in your S6.
The way that they are set up out of the box is for an operating pressure between 300-350PSI.
I haven't set up a sniper style marker for 12grams so I wouldn't really know where to start really. I know that palmer's offers a valve that is built for running 12grams and i think it comes with the valve spring for it. Then all you would have to do is use a maddman spring kit to find the right hammer spring
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"Pumping is about as much a disadvantage for me as shifting is for a Nascar driver" - Ralanti (in an email between ryantuomi, ralanti and I about playing pump) Thunder Bay Pump Club Dementia Paintball MCB Feedback