I've been shooting and loading the 243 since the late 60's. I've always had very good success with IMR 4064 especially with bullet under 90 grains. In fact it's the accuracy powder listed in the 4th Edition of the Sierra Reloading Manual for 80 and 85 grain bullets.You say that after looking at his targets? Gotta be a better powder.
I've never be able to obtain good groups (under 1 MOA) with Hornady 75 or 87 Grain VMax bullets. With Sierra 80 grain Blitz, 85 BTHP's and Nosler 80 BT these bullet shot well under 1 moa with IMR 4064 out all the factory 243 rifles I've ever owned (Winchester, Remington, Browning, and Tikka.)
If the poster isn't getting good results with this powder it might be the bullet choice or some other factor related to the shooter, rifle or scope. Of course nothing is absolute when it comes to rifles and reloading. I'm just saying that it always worked for me no matter which brand of rifle I was using when I was using the aforementioned bullets.