SAPL Mk.I (SOCARs Aluminium Projectiles Launcher Mark 1)

Standard BB Gun shoot 4.5mm bb pellets using pressure from a CO2 cartridge. Single CO2 cartridge consist of pressurized 12g of CO2.

Idea is to construct a launch platform which allow safely puncture the cartridge valve, which allows to create a propulsion from decompression of CO2 gas. This idea was realized in crude concept presented in SAPL Mk. I. It allows to shoot CO2 cartridges by puncturing the cartridge valve.

Plans are available for download here

SAPL Mk. I elements legend:

1. PVC Tube (19mm in diameter, the CO2 cartridge is aprox. 18.95mm)
2. CO2 Cartridge
3. Half of empty CO2 cartridge. Tip of cartrige is punctuated and sharpened nail is coming out of it’s hole. Cartrige is filled with synthetic glue (Poxilina) which connects triangle handle ( 7 )
4. Screw which is used to fix spring ( 5 ) to tube ( 1 )
5. Spring
6. Hole to attach spring ( 5 ) to triangle handle ( 7 )
7. Triangle aluminium handle, used to pass force to spring ( 5 )

Important are points 3 and 7. Half of CO2, empty, cartridge is used because it allows to position sharpened nail directly in center of full CO2 cartridge and also allow to attach the aluminium handle ( 7 ) with Poxilina. In point 7, there is a triangle (90 degree frame) handle, made of aluminium, which allows to easily make a hole in it, and attach the second side of spring.

More plans are available in this PDF document

1. Using sharpened nail to puncture is a semi-good idea. Nail is not hard enought and cracks under hits. Harden steel is suggested.
2. Using relatively soft material (aluminium) for handle is bad idea because it bends and result in not precise impact point on CO2 Cartridge cover
3. Precise hit of nail is extremally important. If its punctuated directly in center it will go straight ahead. In some test showed in video, the hole in CO2 Cartridge made by nail is not directly in center so the cartridge starts to rotate right after it leave „barrel”

Performed basic tests of functionality provided successful results. Primary construction works as intended also is cheap and reliable. It was additionally fasten with material tape.

Shooting at least 3 cartridges using SAPL Mk I. Cartridges were fired down range with mediocre accuracy and distance. Distance ranged from aprox. 10 to aprox. 25 meters, depending on firing angle and other parameters (SAPL grasp etc.)

Measured shooting down range from same position with different angles and with distance measurement. Video footage.

Similar as Test2 but with shorter barrel.

Additional features, such as CO2 position fixing in barrel will be added, which will prevent CO2 cartridge from falling on nail itself while barrel is kept on some angle. Revision 2 (SAPL Mk. I rev 2) will be put into tests 2 and 3.

Ammunition (CO2 Cartridges) used in experiments should be modified for several occasions. For example, extending them with a warhead which would rip thought air easily or a directional flaps, similar to those in mortar shells.

Further plans consist of using coventional shotgun or submachine gun frame and gearbox and constructing semi-automatic projectiles launcher in SAPL Mk. II construction.