I've used the Holland unit for a number of years with perfect satisfaction. It's adjustable so you can measure the TIR on both cases and loaded rounds. The Sinclair unit is also a good one.
This is the Holland Concentricity Gauge with a WS2 coated 50gr Nos BT in a 223 Ackley case:
Darrell Holland is dedicated to accuracy; all his products are of the finest materials and workmanship. His website even has details on his Shooting School and his other gunsmithing and accuracy products. Believe me when I say "he's one of us".
I bought one from RCBS years ago and while I don't need to use it often its always done everything I've asked of it. RCBS is real good too about replacing worn out parts. Never tried a Holland but they make top-notch stuff so you won't be disappointed.
For other concetricity stuff, I've shifted dies to Redding. For the money they're really good, IMO. I also replaced my single stage press with one of theres as well. When in doubt I just swing by Russ Haydon's place (on the way south to Portland OR each week) and his place (with shooting in mind) reminds me of Hotel Street in Honolulu back in the 70's; if he don't have it, I probably don't need it".