In NA, the Swede is most definitely underloaded due to the 'one' WWI Mauser that might blow up.
In Europe, the Swede is loaded to much higher potential. Just snoop around for info on Norma or Lapua ammo IN EUROPE.
The Swede will easily match the 260R. If loaded to 'warm' pressures, will exceed it.
There are many F class shooters who choose this cartridge and have no issue pushing 139/142gr match bullets to 2900fps. This is similar to the 6.5 Mystic/ 260AI.
Used on modern actions, the Swede offers the next size up in case displacement. With the case designed for running smoothly from a mag, an ideal 6.5 hunting rd as a few Swedes have shown over the last many decades.
I would expect to get at least 100fps faster then comparable 260R loads.