There is a reason you see lots of 300 magnums for sale used.
They just are not fun to shoot. The most recoil I would
suggest for a dear gun would be a 308 Win, if you just
have to have a 30 caliber. A 243 or 6.5 Creedmore
or even a 7mm/08 is going to be a lot easier on your
body and ears shooting it. Actually the 6.5 has enough
power for most big game, W D M Bell used a 6.5X54
for shooting hundreds of African game, including lion,
buffalo, zebra etc. He kept a 150 man Safari fed for
over a year shooting that 6.5, and it is less power
than a 6.5 Creedmore. Also he killed nearly 300
elephants with it. Yet you want a 300 magnum to
beat your shoulder to death and go dear hunting?
Here is a link to some background on Bell and hunting
very large game with smaller caliber rifles.
https://huntforever.org/2013/05/06/the-red-man/
Now for the gun. The Ruger American is nice, I am
shooing one at present, and you can get them in
some nice calibers. I also just bought a Remington
783 and I am really impressed with it. It does not
give you the choice of calibers, but if you want a
243, or 308 they would make a nice choice,
in my opinion. Savage has lots of things people like
also, in some good calibers. I have two Savages at
present, both are in some 6.5 caliber.
Take a look at Ruger American, Remington 783, or
some Savage in something like 243, 270, 7mm08, 308,
6.5 Creedmore, and you are going to be a lot more
happy shooting it.