What, for heaven?s sake, are observed velocities and muzzle velocities?
The muzzle velocity of shot is what the term suggests ? the speed at which shot exits the muzzle.
Observed velocity is the average velocity of the shot over the first 20 yards of flight.
For instance, an observed velocity of 1070 feet per second is approximately equal to a muzzle velocity of 1320 feet per second.
Do remember, however, that ultimate velocity ? whether it be muzzle or observed ? is not what makes a good cartridge, as long as it is sufficient to do the job.
Consistency in velocity is much more important.