Short actions refer to the length of that action. This is in direct relation to the length of cartridges that will fit the rifle (i.e. .223, 7mm-08, .308)
Long actions will handle longer cartridges (.300 WinMag and the like) with a corresponding longer bolt throw to chamber a round.
I don't know the "stands" for long and short actions. Maybe another member will help us our.
NRA Life, Lodge 1201-UOSSS
"Si vis Pacem Para Bellum"