I can't see the point of this invention.
IIRC the M1 Garand national match 30-06 load, 173 grain match bullet at 2640 fps, remains supersonic at 1000 yards. And the recoil is not intolerable.
Why would anyone shoot an iron-sighted M1 Garand at 1000 yards anyway?
There are M1 Garand matches but rechambering to 6.5 makes your M1 illegal for these.
If the pressure of he 6.5 Swede is different than the original 30-06 loading, I would think some gas port work would be needed.