A while back I picked up some of the military 172-grain boattail match bullets for .30-06: I wanted to put together some target loads, and dug around for recipes. One thing I consistently found mentioned was 46.0 to 47.0 grains of IMR4895, everyone who mentioned this load raved about accuracy. Tried it, and- depending on brass- the best I could get was about 4" at 100 yards. Which sucks from a rifle that'll put Greek or Korean ball into 2.5".
More digging, and looking in the Lyman manual, decided to try the low load they showed for that range, 43.0 grains of the same powder, as a starting point. Shazam! 1.5 to 2" groups as long as I do my part. And, while the M2 ball hits about 2" high(proper for that ammo and rifle), this load hits dead-on point of aim.
And it does it with more than one brand of brass. You can never tell what will or won't work in a particular rifle until you try it.