I was at the gun shop the other day and saw they had 2 new rifles on the rack , and the guy at the counter showed me the new "center fire" ammo , supposedly 3800 FPS . that's hot , for .17 .
I bought one a while back from a boy needing money. He bought it new . I've shot it a few times. Fun little gun to shoot. It's not good for small game at close ranges. I don't have any real info on them other than that. I'm sure others will give you some better info.