Help needed with a pistol question

[sourdough]

Calipers.

 

[deermanok]

Nice looking pistol.

 

[Sam squanch]

I had one of those. Only 45 caliber.

 

[Grenadier1758]

I don’t know how to do that given that I can’t slug the barrel

Calipers are not that expensive. MidwayUSA has a good selection of calipers so for $20 you can get a decent caliper to measure the inside diameters of your pistol. Not sure where you live but the Harbor Freight digital caliper for $20 is acceptable as well.

Calipers & Micrometers for Correct Sizing when Reloading Ammo (midwayusa.com)

I also use a set of ball gauges for inside dimensions when I have an odd number of lands and grooves. Of curse a caliper is required to measure the gauged diameter.

DGOL Full Ball Small Hole Gage Range 1/8 inch - 1/2 inch 4 pcs Telescoping Bore Gauge: Amazon.com: Industrial & Scientific