If both guns were equal, same weight, pad etc...

IMO it's a serious step up in power. That being said, anytime I was worried about kick, it was never that bad.

Once you can handle a .300mag you can shoot anything IMO, though I've yet to shoot a .458lott, but I'm really not worried.

Give it a shot, guns kick, big deal, in the field I wouldn't worry about it, off the bench its always going to be the worst, if it's too much stop, sighting it in would be the worst part of it, after that, a few shots to make sure it's on, and then just when in the field, I think very few guys would take their 300mags out everyweekend and blast alot of rounds to plink targets.