Thanks Edgar !

As Edgar says

Choke is really the difference between the bore diameter and the constriction at the muzzle

The weakness with the tapered/wedding cake devices is that they only measure the diameter of the muzzle and that they assume a standard bore size. So older bores which may not be modern standard, or back bored barrels will be off

Bore gauges will tell you the true constriction and give you some idea if a choke has been modified

IMHO. If you are going to buy the gauge anyway. Get it 15 to 18 inches long and you can measure the bore for free

If your main interest is measuring chokes you may want to look at MSC for a gage which measures inside diameters from .375- 1.375". The gage is capable of measuring the last three inches of choke, is very accurate, and will accurately indicate how the choke is formed. It has a face similar to a dial indicator with 2 arms, 1 stationary and 1 which pivots. The gage is made in China and have had mine for nearly 2 decades and also use it for lathe work. I paid $75 through Enco at the time which became part of MSC recently.

Only problem with those (and I have one) is on guns like Foxes the chokes are often over 4" long and you can't reach in far enough to get all the choke. That said for other guns with shorter chokes its fine.

I have one of the Enco finger gauges mentioned above. It works fine on most Parker chokes but is limited to around 3". A few years back Dave Suponski offered Starrett inside diameter vernier calipers for sale here. They can measure to a depth of a bit over 5.5" and are accurate to .0001", I think. I couldn't get one fast enough. Not sure how large a diameter they'll measure but the smallest seems to be ~9/16"(.5625") so they're great for smaller bore guns of greater than .410. I'm not sure I've tried on on a 12ga or larger. Dave could likely give a better description. I do know I love this thing.

Looks like it actually can read to .001". Not sure. Dave, where are you?? Yes, it's .001" grads and has an official range of .575" - .750". I think you could measure a bit under the lower limit closely enough for choke measurements. This is not a gauge that Starrett currently offers.

BTW: I got my PP yesterday. I was reading "my" article and concluded that the next time I need a resume, I'm getting Mike to write it!

I have one of the Enco finger gauges mentioned above. It works fine on most Parker chokes but is limited to around 3". A few years back Dave Suponski offered Starrett inside diameter vernier calipers for sale here. They can measure to a depth of a bit over 5.5" and are accurate to .0001", I think. I couldn't get one fast enough. Not sure how large a diameter they'll measure but the smallest seems to be 9/16"(.5625") so they're great for smaller bore guns of greater than .410. I'm not sure I've tried on on a 12ga or larger. Dave could likely give a better description. I do know I love this thing.

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