I work up a load exactly as you suggest, but usually start at 90 grains UNLESS I am using a very large bullet (like I did this year with a 460 gr). Then I start at 80 gr. How big of a bullet are you using?
However, unfortunately I think you need to clean between each shot to find your load. With 777 I literally use spit on a patch and run that side down, flip it and run that side down, then get a dry patch and run that one down: between each shot! I don't think you can believe the accuracy if you try and do anything else. 777 tends to leave a pretty good crud area near the breech plug after each shot. I don't remove the breech plug at all until I am through with that session.
The benefit of cleaning between each shot is that it gives your barrel time to cool, which you will need firing that many shots
Last edited by txhunter58; 11-01-2017 at 05:11 PM.