Haven't bent buffalo horn, but I have worked cow horn to make powder horns for muzzleloading purposes. Boiling in water doesn't quite get the horn hot enough at 212 degrees. Need to get to 230 - 236 degrees at which point it will lose its memory and be quite plastic and pliable. I heat in vegetable oil and use a candy thermometer to control the heat. Slower heat so you can keep it in for awhile to heat all the way to the center of the material will be important. Once you get past the memory it will move pretty fast. Problem is it will be so hot you can't touch it with bare hands which might be clumsy getting it into the jig. So you may want to do a bit, put it back in the oil for a bit and bend in stages. If you are bending in a jig you might want to get a heat lamp setup so you can continue to heat while slowing applying pressure with your clamps.
