best?
I've come to think that a "brush gun" is the suitably powerful rifle that gets through the brush, over the rocks, and up the mountain, the easiest. That usually means short and light.
I also think that no bullets really "buck" brush well, you hit a limb, and the deer is very far from that point, you and or the deer both, are in trouble. I lost I very nice buck this year, undoubtably hitting brush, on a standing deer at about 30 yds. I fully believed I had a clear shot or would not have taken it. Anybody that has not used the "hit a limb" phrase, has likely not shot a lot, or at, enough deer.
I wonder, for conversations sake, if the best "brush gun" might not be a rifle at all?? Seems maybe a 12 ga slug, a 695 grains (?) or more, with no twist rate, and point heavy by design, would have the best chance of continuing in a straight line after contact with "brush"? I dunno, but at one time was giving serious thought to using a pump slug gun in the brush/laurel .