30 years ago a friend of mine who lives to "still hunts" here in the Adirondacks loaned me some fun reading. I believe the book was entitled: "The Deer Hunter's Guide". If memory serves, it was copy write 1964. I just found a copy on Ebay, and ordered it, so I'll soon know if I've found this source.
Anyway, the fella that wrote the book spent a great amount of time tying different types and thicknesses of brush in front of targets and with the brush at different yardages between the firing line and target. From these experiments he deduced characteristics of cartridges that performed well while shooting through brush. If memory serves, and it may not, he found that a 150 grain bullet going 2500 fps or less was most resistant to deflection.
I'm uncertain of the validity of his findings, it would seem a heavier bullet would be better and busting brush, but found his dedication and experimentation interesting. I haven't seen, or read any "brush busting" articles since then. There must be some validity to writings as when I was younger I noticed every "oldster" hunted with a caliber that was pretty close to that description: .32 special, 30-30, 300 Sav, etc. The faster the bullet, the more the deflection. The old timers would sneer at a .243 and other fast calibers. As I consider modern cartridges for deer hunting, I think the nature of the terrain remains a consideration.