losing velocity in Mark II TR? sanity check

[kevwil]

I'm concerned that my barrel is too long for subsonic ammo. This rifle is very very quiet to shoot, and the muzzle velocity seem to calculate out to about 50-150fps below the ammo's claimed speeds (based on measured bullet drop and guessing speeds in a ballistic calculator until find a speed which gives matching drops).

Am I completely off the reservation here? Has anyone else noticed similar effects with 22" Savage rimfire barrels?

[bootsmcguire]

You will discover 2 things here. 1- That barrels have their own personalities and some are more accurate that others and some are faster or slower than others. 2- Ammo companies often inflate their velocities, and in the case of subsonics sometimes lower the velocities a bit extra to be sure they stay low in longer barreled guns vs shorter barreled ones. Just some observations.