What’s the Difference Between Stock Class and Open Class Pump Paintball?

In the pump paintball world, there are two primary classifications for pump paintball markers: Stock Class and Open Class. Simply put, Stock class only uses 12 gram CO2 cartridges and a 10 round feed tube while open class can use tanks and hoppers.

There are also an in between classification called Modified Stock Class. This is basically swapping out the 12 grams CO2 with an air tank or the 10 round feed with a hopper.

What Counts as Stock Class Paintball?

Stock Class Paintball is a style of play where the players are more focused on the fundamental skills of paintball like movement, teamwork, and aiming rather than rate of fire to win. The paintball markers are more restrictive as they must be cocked back after each shot.

Today, most players will identify a stock class paintball setup as any pump action marker that uses a 10-15 round feed that is parallel to the body and runs on a single 12 gram CO2 cartridge that must be unscrewed to change. Upgrades like pump assists, lever change 12 grams, or spring feeds do not count.

The Original Stock Class Rules and Restrictions

Originally, the definition of a stock class pump marker was much more restrictive. For example, the barrels were not allowed to have any porting and there was a limit to how long a barrel extension could be. As the game evolved and new gear became readily available, the rules were adapted to allow exceptions to the changing technology.

Before the adaptations, pump markers like Phantoms, Carters, Gargoyles and most stock class configured Autocockers and Sterlings would not have been originally accepted as stock class.

This left the original stock class markers like the Sheridan PGP, Nelspot 007, PMI-1, KP Rifles and P68SC as your primary go to stock class setups. Understandably, it was a bit frustrating as there wasn’t much variety to choose from and the newer pump markers that the players wanted had features banning them from stock class rules.

If you wish to see the original stock class rules, I have them referenced on the website here.

What Counts as Open Class Paintball?

Open Class Pump Paintball is basically any pump paintball marker with a hopper and tank. The only real restriction for open class pump paintball is that it is a pump action marker.

Most pump players play with an open class pump marker as they are more commonly available and is an easier setup to get use to. Unlike stock class, open class allows for any type of air source like lever changers and constant air tanks. Not only that, they allow for any way to feed paint to the marker like spring feeds, vertical feed sticks, and hoppers.

What is Modified Stock Class Paintball?

Modified Stock Class is basically the in between classification between Stock Class and Open Class. There are so many different ways to configure a Modified Stock Class marker that it is hard to accurately define exactly what the setup should look like, but usually combines aspects from the other two classifications and/or uses spring feeds, lever changers, and auto-triggers.

My Single Barrel Phantom and Double Barrel Phantom that I use can both be considered Modified Stock class as they use spring feeds, lever changers and a constant air tank. They may both share some aspects from Stock Class markers, but they have too many modifications to be called one.