As I posted before, I can measure 1/100 of an inch with a good school ruler or a machinist's scale.

I'm not questioning anyone's abilities with a ruler or anything else; just relating what I found, hence my statement.

My 2 cents worth, spring loaded bore gages, expand take out and measure with a micrometer work shallow & take some pratice to use properly. Have a set never use them, can’t get repeat consistent Measurements. Chinese and cheap, Starrett set may work better.

Inside micrometer is easy to use and accurate. But is also shallow, 1/10 inch or so from the muzzle. Think I paid 60-70 bucks for my Mitutoyo inside mike used. New double that price. Use it a lot general shop work, not on shotgun barrels. Have a Mitutoyo tubing wall thickness mike too, useful but again 1/10 or so deep.

Deeper accurate enough not real expensive the Skeets Gage its the one I use on barrels. Wall thickness I get somebody else to measure for me. Would buy one if I saw a deal.

Never owned one of the inexpensive dial deep calipers. Opinion without experience would not bet a Chinese 5 inch deep dial is as accurate as a Skeets & for sure won’t go deep enough.

William

I think I've talked myself into an Unloader gauge (or maybe you all are responsible for that), despite Dean's very generous offer to loan me his. Now deciding on length and whether to go analog or digital.

Wise decision. Were I buying another one today, I'd still buy an analog dial indicator.

Thing about digital is the battery. I only use one Digital in my shop, Mitutoyo Caliper, and keep spare battery’s to fit, its a good tool & use it frequently, switch to metric & back quick is advantage. Still have Analog Imperial & Metric Dials and often used Veiner caliper for working in fractions.

If I went digital for everything would need many different battery’s & for sure infrequent use likely to be dead when I need it.

Digital no more accurate than quality analog either. Actually one good vintage Mauser brand caliper imperial thousands & fractions one side Metric the other serves all purposes. Inexpensive used on EBay
Look at this one 154025842685

William

I have both analog and digital measuring instruments. For bore and choke measuring I prefer analog (dial type). I like watching the needle swing back around the dial as I enter the choke constriction, and seeing how quickly or slowly it moves. Skeets is a very good gauge.

For weighing I prefer digital.

JMO, SRH

Stan you hit the nail on the head. You are able to visually see the relationship of changes as you're measuring. I feel the same about digital watches, and clocks. You would be amazed at the number of children who do not know how to tell time, and only know what time it is, right now.

I was mentioning this to a good friend of mine, and he just gifted me this nifty little device. Made in Germany, and finished with all the precision you'd expect from those folks; it feels like a fine engineering instrument (which I guess it is). He doesn't remember where he got it some years ago; possibly Browell's. Pulling the knurled handle releases the three spring-loaded ball bearings which then expand to fill the bore. Pull it back to the point of greatest constriction, read the gauge. Viola! While it won't give me decimals it will definitely fill the need I have at the moment. I may still buy a gauge at some point. Or maybe not.

https://i.imgur.com/K4BsB3xl.jpg

Phil, I have 2 of those, although they are neat and I used them 30 years ago they are not that accurate. Better than nothing but they can't compare to my Stan Baker set that measures 10 to 410.