I love the potential that the ultra mags offer. They are workhorses especially in ND. You can load them as hot as you want (with in reason of course
) and there performance can be as consistent as any. I have the 7 RUM, 300 RUM, 338 RUM, and 375 RUM's respectively. The 7 rum is the easiest to get brass for but you can burn a barrel out if you (as Rhian would say) hit the giggle switch too many times in a row without letting her chill out. All the ultras with the exception of the 375 are considered long range caliber rifles with the 300 and 338 most available. I am truly going to try and make my 375 a long range killer. Might take some money though
The 300 win is a very good caliber. I have one. But it just doesn't have the horses that my 300 RUM has and sometimes I like to let those horses run along ways!!
The 7 RUM is not, to my knowledge falling off the map anytime soon. Of course these are just my opinions. Find a gun that you want and love to shoot, and then shoot it all the time. It's so fun!!