I had posted a month or so ago that I had an idea for a superior pellet gun design.
Well, I’ve refined that design and I now believe that if the design could be turned into an actual working pellet gun, it would be the most accurate, most flexible and most powerful pellet gun on the market. Basically my design focuses on removing as many variables from the pellet firing process as possible. In fact I believe it has essentially removed every possible variable, allowing a series of shots of virtually identical power, meaning virtually identical muzzle velocity.
Every pellet gun on the market today has serious issues with variable factors in the pellet firing process. The current design which virtually every gun follows uses a heavy hammer which smashes down on a spring-loaded valve, which quite literally bangs open the valve for a split second allowing gas to escape while the valve is open before the spring and air pressure inside the tank close the valve again.
Even pump action pellet guns use a similar hammer striking a valve approach.
There are multiple problems with this approach.
1. The hammer itself suffers from a variety of mechanical effects which cause its striking force to be variable. Those include friction, position of the gun, spring exhaustion and alignment. Thus while the hammer generally hits with a fairly predictable force, the actual force has been measured to vary by as much as 10% even in high quality guns.
2. The valve has two forces which oppose the hammer, the spring and the air pressure inside the tank. This creates a quite complex curve when you look at how long the valve is open, how much air is expelled from the tank, and how quickly and smoothly the air is expelled. The result is typically a “bell curve” distribution of actual pellet-expelling force. This is because as you reach the maximum capacity of the tank, the air pressure inside the tank can actually overcome the ability of the hammer to open the valve. This is called “valve locking”, and it’s a real problem with PCP guns, especially as the hammer suffers spring fatigue or friction issues which reduce it’s force. A valve-locked gun simply doesn’t fire. However, it’s not a binary situation. The valve itself if usually a modified “poppet valve” which has a “T” shaped hole in the valve so that when the valve is pushed below a seal, the upper branch of the “T” is exposed to the air in the container which rushes out, powering the pellet. When “valve lock” occurs the hammer simply doesn’t push the “T” down far enough to allow any air to escape. But if the valve is pushed down far enough for a portion of the valve hole to be exposed, then SOME air escapes, but it is a constrained flow, which increases turbulence and decreases air efficiency. The end result is that even with higher pressure in the tank, there is less force on the actual pellet. As the air is expelled, the top of the “T” is forced further and further down into the tank, allowing more efficient air exhaust which increases the power until you hit maximum efficiency for the tank, at which point the pellet’s muzzle velocity will be at its highest.
3. From that point on each shot reduces air pressure, reducing efficiency and pellet velocity declines. The reason current PCP designs work reliably at all is because you can exploit this bell curve and get up to a couple dozen shots within a reasonable variation of muzzle velocity such that the point of impact does not move much up to reasonable shooting distances. But it does move.
4. As the air pressure in the tank declines, the hammer knocks the valve down further into the tank, leaving the top of the “T” exposed to allow more air to flow for a longer period of time simply because it travels farther. This is true until the valve reaches the limit that the spring will allow, by which time the gun is usually no longer shooting accurately anyway. Fortunately this effect actually increases the right side of the bell curve described above. There is less air pressure in the tank, but the valve is open longer, providing a larger volume of air which provides more thrust to the pellet, resulting in more shots in the usable zone of the bell curve.
Anyway, my design pretty much does away with all of that. The design essentially provides exactly the same air pressure and air volume for every shot until the air reservoir no longer has enough air to power the gun. There is no “bell curve” of performance, it’s a theoretical straight line from the first to the last shot.
If I could build this gun and it would perform as I expect it to, I could easily sell them for $6,000 each.