I have a Howa LA and a 28" 30 cal 1-10 twist barrel what should I build the 300win mag or a 300 ultra. Intended use will be whitetailed deer, black bear, hogs, elk, moose etc etc. I want to be leathal at at least 1000 yds. How much will I gain by chosing the RUM over the Win MAG? Is a 28" barrel enough for the RUM it will finish shorter maybe 27" if I am lucky.