When You say Buffalo, are you talking about a bison or African ?.
I have taken both, 2 weeks ago I got to shoot one in Florida that broke loose into the Florida turnpike, weighted about 1200 lbs, he ran into a neighborhood and refused to be hearded off, the police did not want to use high caliber Rifles as he wondered from house to house.
The Police captain called me and I came with my #70 Bamboo/hickory self bow, I used Bamboo arrows with real turkey vanes, left helical, and 145 gr. grizzley broadheads, Most cops thought I was nuts, but the captain assured them that I had shot several large animals in africa with longbows, I snuck behind a wooden fence and got to 12 to 15 yards and placed the shot right behind the front left leg ,angling forward towards the chest,The arrow went in all the way to the vanes a good 20 to 23 inches, the Bison made a V line for all the cop cars and people soon scattered into the houses including the cops.
But the animal started to bleed heavely through the mouth and nose and walked 15-20 yaards and fell from the back legs first and then sideways and was dead in 2 to 3 minutes.
It took a flatbed and a crane to carry it to the butchers', 800 lbs of meat was donated to the homeless shelters, the other 2 buffalos killed on the highway were also donated.
I will be doing a shoulder mount of this one, which is almost twice as big as the first one I got in 1985 in Pier South Dakota.
I always use bamboo arrows for large game, first they fly very very fast almost like carbon arrows and they are much stronger than the usual cedar wood arrows, your problem is finding bamboo that is even and you do have to spend a lot of time sraightening them.
Good luck !