Re: What is "Stock Class"
Just an update on this since I feel there may be discrepancies between mainstream tournament rules.
NPPL OSC uses what they call "open class" rules. However, To my knowledge, Their ruling is that the marker must fire one loading per one complete pump, where the stroke of the pump must be a 1:1 ratio with the movement of the bolt. There is some grey area, and Mq'd cockers ARE allowed. They use a 60rd limit, all paint must be checked in BEFORE you chrono, 3 shots are required.
Also, I feel like stock class ruling may be different. I've been told dropouts ARE allowed as long as a knob or housing is unscrewed more than 2 turns, but slam changers and things which hold more than 1 12g are not allowed.