Buy one that is inexpensive and easy to use. No need to further complicate things. You just need to check the run-out of your loaded ammo. I bought my concentricity gauge second hand at a LGS. Cost $50.00, but was well worth it. After buying it, I found out some of my dies were not set up optimally to produce straight ammo. Its probably one of the best pieces of reloading equipment I've spent my money on:

[Linked Image from i.imgur.com]

Originally Posted by raybass
I try to stick with the basics, they do so well. Nothing fancy mind you, just plain jane will get it done with style.
Originally Posted by Pharmseller
You want to see an animal drop right now? Shoot him in the ear hole.

BSA MAGA