Lots of different leagues for pump play (some national, but mostly local it seems), each with own rules. Most fields that limit certain games to pump allow the most liberal variation - that is open class pump play. I'm thinking most of rec fields/games here though. In this case, generally speaking, if your gun is a pump, you're good. But it's really a case by case thing - certain fields have certain rules. In other words, at the end of the day, every field is different. That's a good general rule. Same deal for tournaments, but again while you do have a few national ones with cohesive standardized rules/regulations, you mostly have local variant each with their own rules and regulations. The following is a response to your first/opening post. Wordy, I know, so please forgive me...
What exactly is your first question? Are you interested in defining stock class play?
Per Law's post, it's generally limited to a stick feed (exact quantities of balls vary, but 10-20 or 30 is probably accurate, although more like 20 max a law states), 12g (generally limited to only one) and a pump.
I think of stock class per the old nelson and sheridan based guns, where you also have to rock/tilt the gun to load a ball. I think most people consider spring feeds as "modified stock class," as in not a "pure" form of stock class.
Honestly I don't worry too much about this. There is semi-auto play, which includes full-auto, electropneumatic guns with boards with multiple settings (ramping, burst fire, etc.), etc.
Then there is pump play. This is divided into two main catagories: open class and stock class. Open class uses a hopper, constant air (co2 or hpa tank) and obviously doesn't require the marker to be rocked/tilted to load a ball (this would also include auto-trigger guns). Then there is stock class - stick feed and a 12g, no co2 or hpa tanks or hopper.
Another variant of pump is modified stock class, as alluded to earlier. This allows for constant air tanks (co2/hpa), small pocket hoppers (50-100 rnd hoppers), spring loaded feed tubes that don't require the gun to be tilted to load a ball, etc.
Another way you can think of this is the level to which different forms of pump take the advantage away from the player's equipment to their personal "skill." Open class pump (where no rules apply to gas/power source or ball loading capacity, you just need a pump gun) is one step away from the advantage provided by semi-auto guns. Modified stock class puts some limits on that - small 4oz tanks, spring loaded feed tube, pocket hopper. Stock class is the most "limited" form of pump - the form that requires the player to rely most on his or her own "skill" in terms of shooting/accuracy, strategy, teamwork and movement.
Last edited by toymachine; 12-30-2012 at 06:30 PM.