I've not had a Ruger, only 2 remingtons. Never had an issue with the length of the mag box for what I wanted to shoot.
I had one of the model 673's. I have nothing bad to say about it, the vent rib didn't bother me at all. I shot 220 Speers out of that rifle. Took deer out to 250 yds or so, no problem. It was quite the hammer.
After owning previous rifle for several years I decided I liked the 350 so much I might as well have 2. I came across a gently used Remington 700 Classic. I did the unthinkable and took it to my smith and had 2" cut off the barrel, had a fiber optic front sight put back on the front, complete with hood. It wears a Leupold 2-7 Ultra lite. I shoot 225 Sierra game kings out of this one, they put elk in the dirt, quick. I also found some old Herters 250 gr RN, they are way shorter than the Hornady version. I haven't killed anything with them yet.
With the 20" barrel my 350 is a great dark timber elk rifle, though I wouldn't be afraid to shoot one out to 400 yds. Anything past that I wouldn't be comfortable with this rifle.
Good luck with your search.
