Really very little. They used the same receiver for both the long and short action. The trigger groups are the same, as are the stocks and the pump components. That’s pretty much most of the parts. Like you say, different barrel and bolt, and of course magazines. (Actually even the mags are the same length, just a different follower and a blocker/filler in the short actions). I actually wound up painting the bottom of my mags so I didn’t confuse the 308 and 270 mags.