I have a question about a PGP-II I recently acquired. It is a cartridge valve with a slightly longer barrel than the standard PGP. However, the top tube is the same length as the barrel. My question is, does Sheridan make them like that or is this a custom build? I have seen a member on MCB selling one and he had listed as a PM-II. Just wanted to know if Sheridan had built a new marker that I am unaware of.