[T. O'Heir]

"...a pellet gun is just like dry practice..." Yep. Same principles involving breathing, sight picture and trigger control, but they are not a substitute for live rounds.
CO2 stuff tends to lose power as the cylinder is depleted.
The golden age of airguns was in 14th Century Sweden. Air powered rifles were successfully used as part of the defence of a castle under siege there. snicker. Still a lot more choice than there used to be.