A lot of the speed differences come from the barrel length, free bore and etc. I use a 20" Handi rifle and 13.5 gr of Lil'Gun (this load doesn't fit well in WW brass) with a 40 gr V-Max, R-P brass, CCI400 and 1.93" OAL (that's a little long for most guns) that produces 2790 fps instrumental. That converts to 2815 fps MV.
