STOCK CLASS TERMINOLOGY

OPERATING SYSTEMS (OS)

There are two types

1. Sheridan-based; and
2. Nelson-based.

As far as I can tell, neither of these OS have a performance advantage over the other. It basically boils down to the personal preference of the player. I prefer Sheridan-based OS for no other reason than that was the first OS system I used, so I'm used to it. Most players will tell you that Nelson-based OS are more simple to maintain as you don't require a special tool to pull the valve out, like the Sheridan-based OS. It doesn't make them better, just easier to maintain. Many Sheridan-based OS markers do not have the capacity for interchangeable barrels. My only complaint for Sheridan OS is the fact that you have to tip the marker's muzzle up to load a ball. If you've ever bunkered somebody when you're playing stock and have the first shot miss, you can appreciate the amount of time wasted tipping the marker up and bringing it back down for a second shot.

Usually, in this case, the second shot fired is by your opponent.

VALVE TYPES

Essentially there are two valve types:

1. Sheridan; and
2. Nelson.

The essential difference between the two is that a Nelson valve uses some sort of power tube to transmit the gas to the bolt face when the marker is fired. The Sheridan valves transmit gas to the bolt face through a hole in the body of the marker.

ACTIONS

1. Pump Action
   • This is the standard manual action for stockguns and what most players are familiar with. The pump is connected to the bolt by arms or a rod.
2. Bolt Action
   • This action gets rid of the pump and the bolt itself is pulled back by way of some sort of knob, hook or knurled back piece that allows the player to grip and cock the bolt directly.
3. Lever Action
   • This action is like the Winchester and Henry firearms seen in many western movies. As of yet there are no production stockguns that have lever actions. I am presently working with a machinist to design a robust and reliable lever action design that can be added to an existing marker as a custom modification.
4. Pneumatic Assist Action
   • This is a pump, lever or bolt action but the working of the pump, lever or bolt does not cock the marker. The actual cocking of the marker is performed by a pneumatic ram which is activated when the pump, lever or bolt is moved and opens a pneumatic switch. Think of an Autococker whose four-way switch is not activated by the pulling of the trigger but by the action of a pump, lever or bolt. There are a few pneumatic assists on the market, but they are custom models.
5. Electropneumatic Action
   • This is in the experimental stages, I am assuming that it would work the same as a pneumatic assist but be electronically moved and controlled. There is great potential for stock class markers in this new technology as the electronics could be adjusted and the feed systems made interchangeable so you could essentially have a stock, pump and semi marker in one. The prototype that I know of is designed with a barrel adaptor kit to allow you to use either Autococker or Spyder barrels. (Don't e-mail me and ask about more details on this design, I have been sworn to secrecy by the inventor.)

12 GRAM CHANGERS

1. Plug Type
   • This is where a plug holds the twelve gram in against the piercing mechanism. The 12-gram is removed/inserted through the threaded hole the plug screw into. This is the factory installed system of most Sheridan stock class markers.
2. Bucket Type
   • Also known as a Rat-a-Tac or Phantom quick change. The 12-gram is dropped in a cylindrical "bucket" that threads onto the piercing assembly.
3. In-Grip Type
   • Best known in the Nelson Nelspot, one grip panel has to be removed to insert/remove a twelve gram.

PIERCING METHODS

1. Fixed Pin Type
   • The fixed pin systems essentially has a hollow pin onto which the twelve gram is forced, piercing the 12-gram and powering the marker.
2. Moving Pin Type
   • So far, only the Sheridan-based markers have this system. Basically the valve stem has a sharp pin that pierces the 12-gram when the marker is fired. This type of system required a "priming shot" to initially pierce the 12-gram. This priming shot is notoriously underpowered and will not propel a paintball any great distance. This is taken from airgun technology which is not surprising because Sheridan has been producing airguns for a number of decades.
3. Secondary-Pierce Type
   • This was used in older stockguns like the Puma (not the semi). It was a plug type but the player had to push in a button for the twelve gram to pierce. I don't think there are any modern stockguns that have this system. It was also borrowed from an airgun system used decades ago.

VELOCITY ADJUSTERS

1. Bolt
   • Nelson-based markers use this system. This is because the hammer spring rests between the bolt and hammer so of there is a threaded collar inside the bolt, onto which the hammer spring rests, the collar can be screwed in to increase velocity or screwed out to decrease velocity.
2. Rear Plug
   • Sheridan-based markers use this system. The Sheridan system has the hammer spring independent from the bolt. The spring lies between the hammer and the rear plug. In this type of velocity system there is an Allen screw or lockable thumbwheel that is used to adjust hammer spring tension, much like Autocockers and Spyders. Some rear plug velocity adjusters are also back-bottle ASA's. Depending on the model you can adjust the velocity with the power source attached or it may have to be removed to access the adjusting screw. I have also seen rear plug adjusters which had to be removed from the marker to obtain access to the adjusting screw. These aren't made any more because players want external velocity adjustment without the inconvenience of disassembly.
3. Spring Swap
   • This is the first method ever used for velocity adjustment in paintball. It requires partial or nearly complete disassembly of the marker in order to change hammer and valve springs for stronger or weaker springs as required.
4. Air Flow Restriction
   • Most Tippmann markers use this system. It is a screw which restricts airflow and this can adjust the velocity. However, the disadvantage of this system is that it does not adjust the hammer strike on the valve, so restricting the flow actually diverts gas and causes waste. A bad thing when you're running on 12-grams. To be fair, this system was designed for use with constant air systems, not 12-grams.
5. Adjustable Hammer
   • I've only seen this as an aftermarket product on Sheridan markers. There is a set screw in the hammer that pushes against a ball bearing (at a right angle) onto which the hammer spring rests. Screwing the set screw in pushes the ball forward, thus increasing spring tension and velocity. I haven't seen one of these in about ten years. They fell out of favour as their adjustment range is very limited.

FEED SYSTEMS

1. Muzzle Up
   • This is any stock class marker's muzzle which has to be tipped UP in order for a ball to feed. Like most Sheridan-based stockguns.
2. Muzzle Down
   • This is any stock class marker's muzzle which has to be tipped DOWN in order for a ball to feed. Like most Nelson-based stockguns. Although some custom Sheridan based guns have a muzzle down system, like the Palmer's Super Stocker.
3. As discussed in the OPERATING SYSTEMS section (above) there are distinct advantages to the muzzle down feed system when bunkering an opponent. If you are an "in-their-face" kind of player, I'd recommend a muzzle down feed system because all you have to do is cock the marker as it's pointing muzzle down anyway. (You're standing, your opponent is hunkered down.)

So there you have it. Now you have access to a standardized terminology for stock class markers, components and their function. This page will come in handy as a reference guide if you are trying to get a custom stockgun. Just send the URL of this page along with your request and the airsmith will know what you're talking about.

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