View Full Version : Gauge measuring and chokes

May 20, 2016, 20:20
So I have a fancy schmancy gauge-o-meter (a wedge) and decided to test it against two shotguns I had access to: a 870 and a PW87. The reason I was interested in measuring the latter is because articles like http://www.firearmsnews.com/guns/shotguns/built-for-fun-century-arms-pw87-review/ state it has a modified choke. As I know nothing about chokes, I guessed it meant the barrel was narrowed by some means.

So, here is the Remington:
As you can barely see the "12" tick on my fancy measuring tool, as it is wedged a bit inside the end of the barrel. Does that mean it is a bit wider than spec?

And here is the PW87:
In this one the same gauge seems to be buried even deeper. But I thought chokes constricted the barrel. Am I missing something?

May 20, 2016, 20:40
To measure the amount of choke in a shotgun barrel requires comparison of diameter of the bore before the choke to the diameter at the muzzle.

A change of .005 " will alter pattern density.

I have observed that the bore of 12 gauge barrels produced in the United States will vary widely.
For instance, in my shop I have measured an 1897 Winchester with a bore of .740 ", Remington 870s are typically in the .730"- .735" range, and I had one Ithaca 37 that measured .724 ".

Constriction of the chokes varied just as much.


May 20, 2016, 21:18
Just pattern it.

May 22, 2016, 17:21
Just pattern it.

This is the only "real" solution.