What is the pracical difference between short and long actions?
I'll not open the "can of worms" aspect of this by going on about one being stiffer or lighter or etc., etc., etc..
No!
Just that if you have a rifle built on a long action you might just as well make a benefit from that feature of its size and use a "long" cartridge. That is to say something based on either the 7x57 Mauser or 30-06 cartridge lengths.
Thus 6mm Remington, 257 Roberts, 25-06, 270 Winchester, 7x57 Mauser, 30-06, 338-06, 35 Whelen etc., etc.
You could, of course, equally use that same long action (as did Parker-Hale) on a stalking rifle in 243 Winchester, 7mm-08, 308 Winchester, 338 Federal, 358 Winchester or anything else based on the 7.62mm NATO cartridge necked down or up.
But it won't theoretically work as well (feeding and ejecting) as the cartridge will be "slack" in the magazine and therefore not optimum.
That may be "poppycock" or not but the fact remains that if you have a long action it is better with a long cartridge AND that that same Mauser or 30-06 based long cartridge will be capable of more power than its shorter 7.62mm NATO based same calibre size equivalent.
Also a long action usually allows bullets to be seated "out" of the case again giving more powder capacity. However some cartridges such as the 300 Winchester Magnum as so long as despite being in a long action to not permit this.
LONG ACTION - USE A LONG CARTRIDGE.
7.62mm NATO LENGTH CARTRIDGE - USE A SHORT ACTION.