ORIGINAL: TomFromTheShade
If I was hunting brownies they would know the difference between your 200 grain 30 cal, and my 300 grain 375 H&H lol. When hunting really big bears I don't think that any rifle this side of a 458 Winchester magnum is "too much gun".
I dont think anything would be too much gun for them(I'd take the biggest of what I own which would be the .300rum. If I had bigger, it would be used), but theres no way a .300rum would be too little/not enough. Theyve been killed cleanly with far less.
Point is I wouldnt run out and get a bigger caliber just for brownies. Bullet construction and shot placement always win in the end.