Funny you should ask. I was at the gun range last week shooting my brand new .260 Remington. Next to me was a guy that had a Remington Alaksan Wilderness Rifle from the Remington Custom Gun shop in .300 Win. Mag. We both got there about the same time and we had to wait until the seize fire to put up our targets. At that time, the guy told me that he also had a 7 Rem Mag and asked how much more the .300 Win. Mag kicked. (He too heard horror stories about the .300 Win. Mag.)
I own a Remington Sendero SF in .300 Win Mag, but it has a muzzle brake and special recoil pad from answerrifles.com. As such, the kick is similar to that of a .243. (It also has a very heavy Nightforce NXS scope and, as we all know, or at least should know, the heavier the rifle in a given caliber, the less the perceived recoil will be.)
Getting to the point, I told him, as I will now tell you, that the .300 Win. Mag kicks noticeably more than a 7mm Rem Mag, but is tolerable. When I take off the muzzle brake on my .300, I can certainly feel the kick. In my personal opinion, the .300 is at mine, and perhaps most other peoples', upper limits when it comes to recoil.
Again, it depends on your body size, stock fit and weight, and your personal limits regarding recoil.
BTW, the guy at the range also told me, which I also find to be correct, that the kick from a .300 Win. Mag is sharp, as opposed to heavier calibers which seem to have more of a heavy push.
I recommend that you shoot one before you buy one. Or, you could install a muzzle brake and get a gun that kicks a little on your shoulder, but hits like a freight train on the other end. (Granted, controvery may now arise given that some people, and perhaps arguably so, are very much opposed to muzzle brakes given that they are very loud.)
Hope this helps.
Zachary