I've shot both rifles, and I own a Whelen. I live and hunt country that has moosem elk, grizzlies, and some rather large black bears. I've never been undergunned when carrying my Whelen. The 375 Ruger is a fine cartridge, but it provides little that the Whelen doesn't already provide.
You'll get a skosh more velocity with the AB, though it is doubtful you can measure the difference.
Cartridge : .30-06 Spring. (SAAMI)
Bullet : .308, 165, Nosler Accubond 55602
Useable Case Capaci: 59.818 grain H2O = 3.884 cm³
Cartridge O.A.L. L6: 3.340 inch = 84.84 mm...