Tested three clients guns in my last range session and had some interesting results.
First gun was a 25 wssm and I tried my control lot of IMR 4064 that I've had for about 5 years and found a great load. Then I tested it again with a brand new lot in Hodgdon bottle. The original load was with the control lot was x velocity and had a standard deviation of 5. The new lot was tested half grain below, equal, and half grain above to re-tune the sweet spot. The gun liked the exact same charge, had the exact same standard deviation, and the average velocity was 6 fps slower than the control. Very good in other words.
Then I try a control lot of IMR 4350 that is about 10 years old in a 270 wsm and it yeilds x velocity with an sd of 4. Then the customers lot is tried which is an 8 pound jug and also is in the newer bottles. It gives two feet per second more speed than the control, has an sd of 5 and shoots same size group. Very nice!
Then I try another customers gun in another 270 wsm and it favored RL19. My control lot was about 4 years old and gave x velocity with a standard deviation of 7. The new 5lb jug of current manufacture gives 48 fps more velo and prefers 1 grain less powder to regain the same velos and has an sd of 9. In other words, if getting a new lot of IMR, seems they are doing just fine since Hodgdon took them over. Alliant still has lot to lot consistency problems they require different loads if switching lots. It still shoots good, but dang, these guys need to do something that Hodgdon/IMR have already figured out! I'm about ready to dig up some serious quantities of Norma powder to get the Alliant accuracy without the Alliant problems!
If it's not far, it's boring.