I really wanted H4350 to be as fast as RL17 in my 25-284, since I keep a lot of H4350 on hand. Their burn rates are supposed to be fairly close, but H4350 hit pressure signs about 100fps before RL17 when shooting on the same day with the same bullets and brass. 40-50fps is generally not enough to make me keep another powder on the shelf, but getting near 100fps gain is of interest.
Just my experience....
