Hey Jim and all other 
So then I understand that right and want to reload for my new 280AI
I got nozler brass
H4831sc
Barnes 145gr bullet
Got all recommended from a guy who does a reloading course
But I tried to find a “Note” and done it a couple times.
Every time was different ( first one was around 60gr )
So do I try max load - 2 gr and -4 gr
Then start play with seating the bullet ???
Trouble with load development is there are so many variables to test that to control for all of them, it’d burn out a whole barrel just to find statistically valid results.
So the biggest factors, in order (in my opinion) are:
Try different bullets
Try different powders
Try major changes in seating depth (for example 15 thou off lands and 30 thou)
Try major changes in powder load (full grain difference)
I have a load development worksheet in the load development course that will walk you through the process step by step.
You will see the greatest difference in accuracy in the seating depth’s start there then refine your load with powder, primer and bullet choices.