it depends...do you have a set of outside micrometers?
HOW close are you looking to measure it +/- .001 or +/- .0002
If YES...then snap gauges can be your friend. WARNING cheap gauges measure cheaply. The basic rule of use with snap gauges is you gotta measure 3 times.... 2 times should be the same and 1 will probably be smaller number. Just saying your damn right there is a difference between BRAND UNKNOWN and Starrett.
If you have never used "snap" gauges ....its a feel/process to repeat within .001 (ill advised for beginners shooting for +/- .0002 measuring)
If NO then I would recommend an I.D. mic set
https://www.mscdirect.com/product/details/86424983
Price is a bit hard to swallow for minumal use??? These are tools of my trade for the last 35 yrs. and YES they do last a lifetime (didn't cost that much back in 1987...lol)