The firing barrel is with 12 microgrooves, caliber .25 and fires common pellets. The inverted bolt is made of 1045 steel, the combustion chamber is approximately 20 ml. It has quite a bit of punch, going through 4 cans cleanly at 8X, with only 4 pumps.
It is an evolution of the previous ones, because it has more performance, 4 or 5 pumps are enough to compress the mixture and fire.
The dosing system is the standard one that I designed, and it works very well. Accuracy is excellent.
I used a motorcycle spark plug, screwed into the combustion chamber which makes it fire safely. The lighter is piezoelectric from the big ones.
The main valve is of the o'ring and ball type, which works excellent (it is the "captive ball" valve). The o-ring lasts about 150 - 180 shots before being replaced, which is easy, without having to remove too much.
The front tube houses the small liquid butane gas tank, and has its manually operated valve (pressed with the finger), to introduce the gas to the dosing system, about 3.5 ml.
The sequence of operation is simple: You close the valve, place the pellets in the chamber, introduce the butane and give 4 pumps. The pumping lever, in this case the rear, includes the shoulder rest.
The ball valve - o'ring, is closed by pressing the small stem that can be seen on the back of the gun.
