If you're stuck on a semi auto, I think you have two good choices. Either find an old rem 740 in 30-06, or pick up a semi auto shotgun. Full bore slugs will do a wonderful job on anything in the US at under 100 yards.
If you're open to a bolt gun, I have heard good things about the new mossberg rifles, but I haven't shot one yet. Find yourself an older savage 110 and you'll have a fine, accurate big game rifle, I usually see a few for around $200 at most big gun shows.