Measuring Bore diameter land to land

I have heard many people requesting information on how to measure their land to land bore diameter, Most of the time it seemed kind of complicated.
Also everyone's measurements would depend on their own abilities.
For years I wanted to know the same information, finally I ran across "MSC, Industrial Supply Co, 100 MSC Drive, Jonestown, PA 17038", Phone # 1-800-645-7270
web address. https://www.mscdirect.com/product/details/64507940

I ordered "Class ZZ Minus ZZ SPI Black Oxide Pin Gauge" in sizes .499 thru .503 the shipping was $11.00 (I thought kind of high) and the gauges were $3.85 to $5.00 something each.

When they got here It took me less than 5 minutes to measure all 5 of my black powder guns.

If you had some buddies to go in with it would be cheaper, you only need them once on guns you have and buy.

Personally I thought it was worth every penny

I have an entire set (0.250"-0.500")I bought years ago at an auction. I use them more than I thought, you'll find them handy.
If you have even number of grooves, I also use a telescoping gauge (gage) to get my bore measurement.

I use the Thor sizing pack.

https://www.muzzle-loaders.com/thor-bul ... -pack.html

That Thor sizing pack seems nice.. I guess the next easiest option is to experiment with bullets & sabots one has around to get the perfect bore fit.