The only factory loads I've ever chronographed was the Winchester 45 grain JHP .22-250 load, which is advertised to reach 4000fps. Out of my Ruger M77VT with it's 26" barrel, this load clocked and average of 4016fps, with an SD, if I recall correctly, was right at 10fps. So yes, this load, in my gun, lived up the the advertised velocity, but I will tell you that it is a very hot load, and I've had several rounds show mild pressure signs.

Mike