This one is all in the hands of the breach man lest when flowing into different rooms an unexpected hound is encountered. I think the shotgun would be the best weapon for all the reasons you mentioned TS (penetration & accuracy). Only problem is if you can't chamber that round in time your goose is cooked. Your buddies will probably have to beat the thing to death after that. My SAW would make short work of a dog, but the potential for collateral damage...
