Cartridge over all length
I’ve read that there is a relationship between seating depth the jump to Lands and groves. But my data says there is a stronger relationship between case design and seating depth. I would assume that the relationship is case volume or density and seating depth.
The short answer is Yes, all of the above have an effect as does the jump to the lands. I would suggest you stick with one type of case. LC match is good stuff. Down load the powder by 2 grains then work up in .2 grain increments until you find the "sweet spot" then start with the COAL. then do it over. when you get it as good as it's going to be. you can change something else. powder, case or whatever. the trick is to only change one thing at a time. you will find that the best load with LC brass wil not be the best for winchester or ever other case type. Are you trimming your cases?