Choke gauge - professional model

[Rick Roemer]

Any preference digital or analog?

[Pa SxS]

With the analog mic, you calibrate the gage using calibrated rings of a certain diameter. For instance, you calibrate the mic using the .700 ring when measuring a 12 bore barrel. You use different shafts depending on the gauge your measuring but you unscrew the gage and screw it on the different shaft, at least that's how my Stan Baker mics works. Never used a digital one but it's probably similar.