About to load my first 250 and 303 reloads. What is the COAL for these cartridges?

Depending on the bullets used and your throat dimensions those COAL's could change, but are a good starting point.

Make sure they feed through the rotor and chamber before you load very many.

I finished up with the 300 Savage I started last winter today and knocked out 49 303s (crumpled 1 case). 1\2 with 170 Speer FPoints, 1\2 with 180 gr Speer RN.. All at 2.520 work through both the H and the G. Will have to work on the 250s later firewood to get up for if it ever gets cold.