Well, I felt lucky to get it because I had just started to look for one when this one popped up. The mainspring and piston is serviceable easily without a spring compressor. Power is exactly at the level I need, quiet, soft shooting, crisp, accurate. The list goes on.
Thanks for the compliments guys.
As for attachment, it's a very snug fit. I think the gun it was meant for has a slightly smaller barrel OD. So this one I installed with a rubber mallet. It was intended for a grub screw, but I left it out. I dont like using them, and if I do, I get a brass set screw or one with a nylon insert. I've damaged barrels before. Not that I can tell or say for sure with any set screws. But the amount of force needed to create a low spot in a barrel from the outside is not as much as you'd think.