Straightshooter, that is quite the list, thank you. Interesting the differences between the stated and actual. Reason I asked is I am getting a High Standard Supermatic and it is recommended to use only regular velocity ammo. Merry Christmas, Jim
Merry Christmas to you too.
Of course, there are various things effecting the differences between what was recorded and what's stated, barrel length (the number in the far right column) being the primary thing. Then there's variance in barrel construction and of course there's variance in chronographs and their accuracies.
For Lapua Cmidas+ out of my Ruger Precision Rimfire 18"er I got velocities pretty darn close to the published velocity . . . regularly. And as one might expect, the SD's were pretty good (they'd better be for what they cost

).
Though all rimfire cartridges tend to have a lot of variance compared to what one can get with center fire, there are some that tend to be pretty good, Cmidas+ being one. And out of my guns, these are some others that have worked well for me:
CCI SV's
Eley Club
Eley Tenex
Federal AutoMatch
Federal UltraMatch
Lapua Center-X
RWS-R50
SK Long Range Match
SK Rifle Match
SK Standard Plus
Wolf Match Extra
Wolf Match Target
The worst being:
Aguila Interceptors
CCI Blazer
CCI Velocitors
CI Super CI 1500
Federal Value Packs
Federal Champion
Norma Match-22
Remington Cyclone
Remington Golden Bullet
Remington Golden Bullet HP
Remington Subsonic
Remington Thunderbolt
Remington Yellow Jacket HP
RWS High Velocity HP
RWS Target Rifle
Winchester Bulk
Winchester Super-X High Velocity
Winchester Super-X Hyper Speed HP
Winchester Super-X Power Point HP
Winchester Super-X Standard
Winchester Super-X Super Speed HP
Winchester M-22 Bulk
Winchester Match
Winchester Subsonic
Winchester Varmint HE Fragmenting