| The valve / piercing pin are a tad dull, and /or your velocity adjuster is backed off to far or weak.
Your PGP's hammer strikes the valve pin and in turn the pin continues to travel forward having its other end with a sharp point pierce the end of the 12gm cartridge. If the point is dulled it makes a VERY small hole in cartridge, and if not struck hard enough by hammer just does not have enough impact to make a sufficient hole in the 12gm seal. |