I banded my boer wether, a companion, after he strangled another goat to death when his horns got caught in her collar. My fault for leaving the collar on, but because his horn are small, I went for it. I used the green bands used for wethering with a cheap bander.
Not a fun experience, especially for him. It was very painful. Horns take a while to loose the blood supply, and thus the feeling. So he felt pain and pressure on his horns for a while. Before I applied the bands, I gave him a dose of banamine. I also dosed him every twelve hours for a few days. If I didn't, he would grind his teeth, and also cry out if the slightest thing brushed his horns, because it hurt.
He also refused come near me, because I was the one who did that to him. The first horn came off after only two weeks, very premature. Thankfully, it did not bleed too much, I was able to catch him and hold pressure to it. The second horn came off a month later. I changed the bands every two weeks, also so I could check the progress. They began with a slight indentation, and those got deeper and deeper each week. I actually used several bands per horn, in order to compress the absolute base of the horn. It worked quite well.
That entire time, he was terrified of me and unhandleable. It has been a few months since the ordeal finished, but he still isn't as friendly as he was before I removed his horns.
So if you do it, please do use a pain reliever, because they really do need it.