This is a high quality caulking gun. Delivers a force upon the piston of over 70kg. Proper quality cast handle and robust design throughout. Ideal for P3.
The cartridge configuration of P3 has 2 chambers, one behind the other, they move in unison. This means that when the cartridge is empty the rear piston is halfway down the chamber; hence you need a gun with a robust mechanism to provide the force required to dispense the material, particularly in cold weather.
Not rocket science, not expensive, just a good quality good value gun.