I have both a 7 Mag and a 300 Win Mag. There is a pretty big difference in recoil.

I can shoot easily a 100 through the 7 Mag and my shoulder is a tad sore. I shot about 60 or so last week and left range thinking my shoulder is pretty sore. Next day was all bruised up nd the 7 Mag did not do that.

The 7 Mag is pretty low recoiling. The 300 is manageable but keep in mind you cant shoot as much at a time.

I like shooting both, but given a choice like the 300 better. I like a little more recoil, tells you more power.

Now those RUMS I am not sure of. I do like to shoot too much and would hate to go and shoot a few and leave.

IMO perceived recoil is mainly in the mind and ears of the shooter. The rest comes with practice and fit of the gun. If the stock isn't a good fit it'll beat you up. Example Rem 7600 in 35 Whelen, the wood stock w/ plastic but plate hit like a ton of bricks. Replaced with a cheapo Ram-Line synthetic with a recoil pad, less than half the weight. Believe it or not it reduced recoil by half. Now it's the perfect compliment to my other woods gun a m94 in 307 win. You have to try different guns to see what's most comfortable. A 308 is never too little gun. In my experience most people tend to be more accurate with lighter recoiling rounds. With my 223, 243, 257 and 6.5 are joys to shoot and fatigue takes a while to come. The 270 wsm, 307, 06 and 35 comes a lot quicker. My range sessions usually start with the smallest / ligthest recoiler get shot first to stave off the flinch from fatigue and usuall last around 120-150 rds depending on what I'm shooting. Getting used to a particular gun and how you roll with it can also affect how you perceive the recoil.