Free: Contests & Raffles.
IMR-4350. I'm not so worried about small variability from lot to lot, but I guess the variability might be larger than I suspect.
Too many additional variable other the powder lots, such as brand of brass, twist, throught and leade, etc...agree JD. Start loe, work up watching for pressure signs and accuracy drops and gains. Seen too many blown barrels, missing fingers, and scarred faces to comment otherwise..
I use the book as a starting point and let my rifle tell me when enough is enough. Work up means just that. I've had several rifles that liked a good deal over max listed load. I don't use the book listed coal either. My rifles tell me where to seat them.