Evolution of the Paintball Marker

The Legend Paintball Marker

The Nelson Paint Company started in 1940, originally served the forestry market by producing premium tree-marking paints. Faced with the challenge of marking trees in hard to reach places, Charles Nelson invented a paint pellet that could be shot out of a gun.

The original pellet was made from oil base paint in order to leave a long-lasting mark. Foresters marked trees with it. Cattle ranchers marked livestock with it. Eventually due to human nature people began marking each other with it. As pellet marking became a more regularly played game, Charlie Nelson was asked about creating a less permanent type of paint in the pellets. Thus the water-based paintball was born.

The original paintball gun, the Nelspot 007, was developed by Daisy, a company well known for its air-powered BB and pellet guns. Like a bolt-action rifle, cocking action was manual via a lever on the side of the gun. The balls were loaded from a tube running parallel to and above the bore, which means the gun had to be tilted to allow balls to roll in every time it was cocked. The power source for the gun was a 12 gram Co2 cartridge, commonly used in BB and pellet guns. As with Daisy's other air guns, the Co2 cartridge was stored inside the grip frame and accessed through a removable grip panel. A stock 007 would get around 20 shots before the cartridge had to be changed.

The Nelspot 007 was a popular paintball gun, for both rentals and as first-time purchases. When compared to its nearest competitors, the PMI/Benjamin Sheridan PGP and the National Survival Games Splatmaster, the Nelspot spawned a much larger upgrade path. Early Nelson based paintball guns were truly "Nelson based" - having been sold as upgrade kits for the 007. For years most of these paintball guns - even the ones completely manufactured by other companies - had 75% parts compatibility with each other and the 007. That is not really the case today. Many of today's popular pump paintball guns, including the Component Concepts Industries Phantom, the Maverick/Tracer series, and current Brass Eagle pump paintball guns, as well as the Advanced Tactical Systems AT-series select fire paintball guns, are based on the Nelson system, but do not use compatible parts with their predecessors.

THE SYSTEM

Over the years, there have been many variations of the internal systems of Nelson based paintball guns, including different configurations on nearly every internal part of the paintball gun. While all Nelson based paintball guns may not have interchangeable parts, they do function the same. The Nelson internal system consist of several moving parts including a bolt, hammer with connected sear and sear spring, valve tube and cup seal, main spring, valve spring, and trigger. Pumping the paintball gun requires one stroke back, and one stroke forward. Although the original Nelspot 007 used a small bolt-action like screw to pump, everything since has had a wrap-around pump handle connected to the bolt.

Gas enters the paintball gun through the valve body in the rear of the paintball gun. The cup seal on the back of the valve tube is held against the rear of the valve seat by pressure from the gas itself, and the valve spring. The sear on the hammer pivots on a small pin and is held in it's normal position by a small spring. On the backward stroke, the bolt moves rearward, compressing the main spring until the bolt and hammer are joined and hooked together via the sear. Note the hammer is held in place by the valve tube ledge. At the same time, a ball drops in place in front of the bolt.

On the forward stroke, the bolt moves forward, carrying the locked hammer and compressed main spring with it, while pushing the ball into the bore of the paintball gun. The paintball gun is now ready to fire.
When the trigger is pulled, the rear of the trigger lifts the rear of the sear. As the sear pivots, the front end unhooks from the bolt. The compressed main spring throws the hammer backwards very rapidly. When the hammer hits the valve tube ledge, it pushes the entire valve tube backwards. Gas rushes into the holes in the rear of the valve tube, travels forward through the tube, impacts the ball, sending it down the barrel. The valve spring then pushes the valve tube forward and closed. The paintball gun is now ready to cock again.


BOLT AND HAMMER TYPES

 Breech or Bore

Bolts vary from brand to brand, but there are two common types. The Phantom, for instance, is what is known as a "breech drop" paintball gun, while paintball guns like the Line SI Bushmaster are a "bore drop". The most obvious noticeable difference is the length of the bolt. On the Nelspot 007, the bolt was the shorter "breech" type. The main operating difference is that the ball drops into the breech area, and must be pushed up a small step to be seated in the bore. The "bore drop" type simply drops the ball into what is basically the bore of the paintball gun. The theory behind the development of the "bore drop" was that the step on "breech drop" guns was part of the problem in pinching balls as the paintball gun was cocked. The "bore drop" concept eliminated the step, thus eliminating the alleged problem. This was used as a major selling point for "bore drop" paintball guns. Whether it makes a realistic difference or not is an entirely different discussion. I have owned a multitude of both types and tend to favor the "bore drops".

 Anti-Kinkiness

The Nelspot 007 could be sort of stiff to pump, especially on the forward stroke. This was caused by kinking of the bolt and hammer. When the bolt and hammer were locked together with a compressed spring between them, they would kink, causing friction against the interior walls of the paintball gun. Several styles of bolt/hammer combinations were developed to combat the problem, each of them using a different method of holding the bolt/hammer combo straight once they are locked by the sear.

• The top system uses a collar around the hammer which fits inside the back of the bolt. The design  works well and is used on the Phantom, and was the stock design of the Line SI Bushmaster. In the case of the Bushmaster, the velocity adjustment tension screw for the main spring is inside of the hammer. 
• The middle system uses a shaft coming out of the bolt, which ran through the center of the hammer. Later versions had the shaft also act as the velocity adjusting tension screw (mentioned earlier). This meant the shaft rotated and extended backward to increase the tension. This maneuver will also increase the level of "frictionless ness" on some paintball guns, however, the shaft can be turned back so far as to interfere with the mating of the bolt and hammer.
• The bottom system appears on the Maverick/Tracer series. It involves a shaft protruding from the hammer which fits inside the bolt. This shaft also acts as the forward end of the valve tube, leaving the paintball gun with a very short valve tube that extends only as far as the back of the hammer. The ATS select-fire paintball guns use this same method.

PROBLEMS

Gas leaking down the barrel on a Nelson based paintball gun is indicative of a bad cup seal. The cup seal wins the "most likely to wear out first" award for Nelspot paintball gun parts. That's not to say that they will. I have some Lapco pieces that I have been using for years. However, on stock Nelspot paintball guns, and a lot of the clones, the cup seals were definitely the most frequently replaced part. The only other critical air seal on the paintball gun is the O-ring on the valve seat. I can't recall ever having a problem out of one of those, although it is feasible that you could damage one when removing the valve.

Older valve tubes used to be bad about breaking in colder weather. The break would usually occur at the threads where the cup seal screwed on. Ever since the advent of plastic cup seals, I have not seen any break. Other parts to watch out for are the sear, which can wear out after years of excessive use, and the thread holes on body parts. Most Nelson type paintball guns are made of aluminum, and repeated disassembly can take its toll on the threads. Other than cleaning, the paintball guns generally require little maintenance.
Popping

A common occurrence on Nelson based paintball guns is the "popping" sound on the backward stroke of the pump. This can happen for several reasons. First off, it's important to understand why most* Nelson based paintball guns cannot be cocked without gas going into the paintball gun. As mentioned earlier, both the valve spring and gas pressure hold the valve tube in it's forward (closed) position. The valve tube ledge in turn holds the hammer in place so that it can be locked with the bolt on the backward pump stroke. If there is no gas in the paintball gun, the valve tube will not be held in place, which means the hammer will not be held in place. This means the main spring will push the hammer back out of the reach of the bolt on the backwards pump stroke, and thus the paintball gun cannot cock (although it will load balls into the bore).

The popping noise is caused by a small release of gas when the valve tube is opened on the backward stroke. The most obvious reason for this is because of low gas pressure not holding the valve closed. In fact, the "popping" noise is often a nice audible warning that you are exhausting your supply of gas. The noise can also occur if there is too much tension on the main spring, and the spring pushes the hammer against the ledge with excessive strength - in other words, the velocity adjuster is turned up too far. In this case the adjuster needs to be turned back down, and proper velocity should be sought with the use of a spring change.
*If a Nelson based gun has a very strong valve spring to hold the valve tube closed, it can be cocked whether it has gas or not.

Semi-automatic Nelson Paintball Guns

There are only a few semi-automatic paintball guns based directly on the Nelson system. Each involves a pneumatic cocking system attached to the bolt, as opposed to a manual pump handle. The Brass Eagle Rainmaker should probably be considered a "half Nelson" since the hammer/sear system is similar. It is a strange hybrid of a Nelson/Sheridan paintball gun.

To my knowledge the only Nelson based semi-auto paintball gun remaining in production is the ATS series of select-fire guns. They use internal parts very similar to those found in the Maverick/Tracer series. In addition, ATS paintball guns have a lever mounted near the valve tube ledge which is tripped by the hammer and activates a 4-way valve. In a similar fashion to the Worr Games Autococker, the 4-way valve directs gas through a pneumatic ram. The ram pulls the bolt back for cocking. When the bolt connects with the hammer, the 4-way is tripped the opposite direction and the ram pushes the linked bolt/hammer forward. The unique thing about the ATS paintball gun is the fact that the pneumatic operations are tripped by the hammer action, as opposed to trigger action. This completely eliminates the chance of "short stroking" the paintball gun, which is a common user mistake on paintball guns with trigger activated pneumatics.

For a short while Worr Games did produce a semi-auto conversion kit for Nelson based paintball guns. It worked in an identical fashion to the company's Autococker, with the pneumatic cocking system being activated by the trigger action.

As I was recently reminded, Lapco also made a pneumatic cocking version of their Nelson based pump paintball gun. It was similar to the Worr Games kit in that the pneumatics were activated by the trigger action. There were reportedly only 150 of the paintball guns sold.

There was also kit made by PMI for the Maverick/Tracer series called the Chameleon. It was a side mounted pneumatic cocking conversion which, like the others, automated the pumping process.

PERFORMER

The design of Nelson paintball guns is extremely reliable in nature, while offering great performance for a pump paintball gun - but performance is a relative term.

The most impressive part about Nelson performance is, to me, the one that counts the most - consistency. When I think of consistency in velocity and consistency in accuracy, I think Nelson based pump paintball guns. If you are looking for accuracy, Nelson based guns can certainly deliver. If you seek efficiency, they can be tuned for that too. And even if you want a good rate of fire, A nelson based paintball gun can be surprisingly fast, when set up properly. Back before the almost complete saturation of the semis, many teams still played competitively with pump paintball guns.

Most of the guns include an "auto trigger" which allows the user to simply hold the trigger and pump. By tuning to use a light main spring, heavy weight hammer, and friction free internals, an experienced player could easily match the rate of fire of many of today's entry level semi-auto's. Pump play has since gained the reputation of the "one shot" or "low volume" way to play. However, I think many of today's players would be surprised to find out just how much paint was shot and just how fast it was shot during pump tourneys a decade ago.