4-5 grs. of Unique under that 115 gr. bullet should do all you need done with that rifle and cartridge. I've been shooting the 32-20 in revolvers and rifles since the early 80's and it's one of my favorite cartridges. I would try to use a bullet with at least some kind of meplat rather than the traditional round nose. My '92 fed the RCBS 98 gr, KTSWC ok. I doubt you'll need to anneal the brass. The case necks are so thin you can crush them with you fingers. Go easy loading it. Ham-handedness will only result in crushed necks.