Normally, the grain weight of powder and the grain weight of the bullet, along with the rifle's weight determines the exact recoil expressed in foot pounds force and recoil speed in feet per second.

For a human's interpretation of recoil, more comes to the table - one man might be kicked more by a certain ctg. and stock design, than another - and so it goes.

Some men are litterally knocked off they feet by very much less fpe of recoil, than another, both being equal weigth themselves. Recoil is so subjective, it's a very difficult subject.

All that said, I've shot Remington Model 700's in .280 and .30/06 (identical guns), both with 150gr. bullets and both loaded to the same 3,050fps velocity - seem to me, the .280 kicked less, but - perhaps not.

To compare 2 rounds for recoil, they'd have to be shooting the same weight bullet, or perhaps normal weight bullets for the calibre - in typical rifles for both - then, the small calibre with lighter ejecta produces less recoil - usually. Powder weight/bullet weight/rifle weight - those are the positives in recoil production. The person's weight, build, height - experience, all come into how he interprets the recoil actually produced mathematically.
I shot a friend's lightweight .30/06 Savage - about 30 years ago, that kicked like it thought it was a .338- and that was a factory RP 180gr. load. I've a friend who owns a custom .338 WM custom built on a P-17 Action with Bastonge stock,weighing 10 pounds with scope that kicks less than most all .30/06's I've shot, except for another Bastonge sustom .30/06 that felt like a .270 - go figure.

Since most 7's shoot 160gr. normally (or very slow (lightly loaded) 175gr.), and most guys (here) use 180gr. and 200gr. in their '06's with either hot handloads or factory, I'd say the .30 cal should kick more - just about every time.

The reason for using .280 is I've never shot a 7x64. They are VERY similar and I suspect most handloads are interchangable. I have shot an overunder 16 bore/7x65R, - which was quite heavy and felt like shooting a little 6mm Rem, even though it was using 56gr. of powder, the bullet weight was only 140gr. Very load 'felt' recoil.

I've never shot a .30/06 that kicked as little as that 7x65R.