Measuring chokes

[Ray B]

I recently purchased a SxS 16ga and the seller said the chokes were .015 and .028. I looked up chokes and these correlate to Modified and Full. But I don't have a method of measuring the constriction other than measuring the muzzle, which I did. I got .647 and .634". Using .662" as the unconstricted bore of a 16 ga it does work out that the .662" bore is reduced to .647 & .634". So if my information is correct then I do have a shotgun with Mod & Full chokes. Is this correct?

 

[BeeMaa]

It depends. Each manufacturer has their own specific measurement for what is considered “cylinder” and everything else is based on that.

Example. My SBE3 12 bore cylinder choke is measured at .725”, while my friend’s Browning Maxus measured cylinder at .740”. This means that my cylinder choke is equal to his light modified choke.

It depends on what the manufacturer determines cylinder choke to be. From there they usually go down in size by .005” at a time but even then there could be variations. Even then, I’ve seen .010” variations within a manufacturer between models for the same “choke”.

In the end, it depends. So more information is needed on the specific firearm.

 

[Ray B]

The firearm is a Parker VH dated 1910 16 ga 2 5/8" chambers.

 

[BeeMaa]

Don't hold me to this, but it's close for a 16 bore.

CYL .662"
SKT 1 .658"
IMP CYL .655"
SKT 2 .652"
MOD .647"
IMP MOD .642"
FULL .634"
EX FULL .627"

Looks like you have a MOD and FULL choke and you are correct. Shoot the proper loads, shoot straight and in good health. I'd also stay away from steel and TSS for sure.

 

[steve white]

Measurements as related to what 16 ga. barrel? Many early Continental guns not only had tight chokes, but tight barrels, almost beyond the low side of standard tolerances tight, ESPECIALLY in 16 ga. And that is before we even get started on proprietary ammo and early non-standardized shotshells.

In any case the measurement of the bore still determines the ratio to the choke boring. Shooting patterns is the best comparison, something few do. If altering fixed chokes it must be done if you are to know what you are getting.

 

[BonUm16]

You need a bore gauge to determine the measurements for your gun if you really want to put names/numbers to the chokes in your gun. Even then, those numbers are kind of irrelevant. Choke can be manipulated in many ways (speed, shot size, shot type/hardness, etc.). A Mod choke might throw a true Mod pattern with one load, an IC with another, a Full with yet another. That would be extreme but the point stands.

If interested, I can check my Parker Serialization book to see if it’s in there, Ray. I’d need the full serial # if you want me to look it up.

 

[Coop453]

Maybe the seller did know how to measure and his numbers are correct? And...like Randy said, for you to do the measurement you need a way to measure the bore in each barrel. For about $20 you can buy a long shank telescoping bore gauge. But to use in in a fixed choke gun you need to reach in and set it and then drop it through the bore to retrieve it and measure. Or find a real shot gun bore gauge. Me, I would accept the sellers measurements and then go shoot a piece of paper to see what it looks like. I think you have a shotgun with mod and full chokes. And some 16 gauge guns shoot very tight patterns with full choke.