Ralph, the Hornady 8th. Edition shows a max load for a 129 gr. to be 42.4 gr. of IMR 4350. Just a caution to you. If you load one bullet you should consult that MFGR.'s manual. Good luck on finding a load.Yeah I have the nosler manual but with so many old Mauser rifles still in use both nosler and Hornaday list loads on the lite side. I wonder if I could use 260rem load data as a starting point and work up, but I'm a rookie reloader and I'm not sure that's a good idea. What I Really need is someone to recommend a good powder I have Imr 4831, h414, Imr 4350, A4350, Imr 8208xbr. Just need to know we're to start. I'm not dead set on 129 gr's either I'm open for info on 140's.