Shane,
I assume the brass that you're resizing has been fired form the same rifle right?
1. If the answer is yes, get a fired case that hasn't been resized and measure it with the
bump gauge (as in shoulder bump). Write that number down.
2. Your target size is .002 less then a fired case. Not shorter, but not longer or it won't chamber.
Having said all the above, I was not able to have any success with Hornady New Dimension Custom die. I got stuck cases, cases that wouldn't chamber, and cases that wouldn't extract from the rifle, etc... Finally a guy from my range after listening to my tales of whoe came to my house looked at my set up, tried it and told me to get rid of the Hornady dies and get some Redding dies. I did and magically all my resizing problems went away.
I don't want to start a war with all the sales rep on this site, but Hornady sells a lot of stuff, but most of it it's not very good. I have the LnL AP press, the Case Prep Center, GS1500 scale, the hand primer, etc... Some I still use, some I've managed to sell, others just sit.
My advise is cry once and buy what will work and save you time, but most of all frustration. Here's what I know that works
http://www.midwayusa.com/product/267...ProductFinding
Here's the big question since you're reloading for 22-250, 270 and 300 win mag. Are you reloading for precision or just for "good enough" reloads?