Anything that is short, handy and you can aim quickly, I suppose.
They have done tests on "brush guns" and deflection. The big, slow and heavy rounds did no better than the lighter, smaller faster rounds. An interesting point was revealed in one of the studies: No branch can deflect any bullet. A piece of metal going 2000 mph isn't going to have its direction changed by a wispy branch. What the branch does is make the bullet expand a little. Now the shape/aerodynamics of the bullet has changed, causing it to steer off like an improperly tuned arrow/broadhead. A flat nosed 45/70 bullet may deform even more than a 30 caliber spitzer. Causing it to veer off even more.