AR chambering method while load development

[Drifter]

Its just a little tricky trying to shoot round robin OCW with single
Rounds of each charge weight all loaded in a mag

I wouldn't bother with single loading for a round-robin OCW. Consider loading the same number of cartridges in the mag as you have loads. Five is a good number.

Write down the plan to make it easy to follow. For example:

Number your loads 1 through 5
Number your targets 1 through 5

Five strings of five shots, so this will be the target (shooting) sequence:

1-2-3-4-5
2-3-4-5-1
3-4-5-1-2
4-5-1-2-3
5-1-2-3-4

Simply load five rounds into the mag in reverse order, and shoot the targets in regular order. Check off each string as you complete it.

Do it twice to confirm results.

Yeah, I know. But I don't shoot one shot every 1.5 minutes, when not doing load development, either.

I'm not waiting 1.5 minutes to shoot whether I'm developing loads or not. If the load is overly sensitive to time between shots, I'll find another load (or another barrel).