I've been looking at the 5" conversions, and I see they offer 2 part numbers. One is 512504, the other is 512506. I know the 504 is for the older guns,and the 506 is for the newer design, but is there any real difference ?
Not sure about the numbers but the original P22 was based on the P99 style. In about 2010 or 2011 the design was changed to the PPQ style. There is no change to the barrel, barrel sleeve or barrel nut, but the slide and stabilizer that comes with the newer pistol has the same PPQ theme. The old stabilizer was based on the P99. That is the only thing I can come up with. CA pistols don't allow a removable nut so theoretically,,,,you can't change the barrel...but of course where there is a will there is a way. If you have a Q model pistol, BB,BC, BD...etc. you need to the Q style stabilizer. It basically covers the muzzle end of the longer barrel. 1917