I am relatively new to Handloading. Have a .223 Savage 10FP. I have Two powders on hand (H322 & AA2015).
My question is in selecting a load, what portion should I step up at. If the manual list 21.7 as a starting load,should I step up in 1 grain increments till I see pressure signs or reach my smallest groups? Should it be 1/2 grain increments or must I go in 1/10th grains?
I don`t want to do something that might damage my rifle or me, but would like to work up loads quickly.
I have a day off next Thursday and was planning to load 5 steps of 10 cases in each step to find which works best for testing Thursday.

I generally subtract the listed minimum charge from the maximum listed charge. Then, divide the result by 19. and use that as the incremental increase from the minimum charge.

For example:

Say the manual lists 28.0 grains for a minimum load and 31.0 for the maximum...

28.0 29.6
28.2 29.7
28.3 29.9
28.5 30.1
28.6 30.2
28.8 30.4
28.9 30.5
29.1 30.7
29.3 30.8
29.4 31.0

On cases smaller than 308 size I go up in .3 increments from starter loads. On 308 and larger, I go up in .5g increments. Anything less doesn't have much effect.