choke size

[tote4570]

I have a Stevens 820 12g shotgun with a 2 3/4in chamber. I was wondering how to find out what kind of choke is on the gun. I cant find any markings for it.

[oneounceload]

There should be some marking on the barrel, close to the breech end, whether in words or symbols, I'm not sure. One way to determine the ACTUAL choke is to pattern it. Many guns come marked one choke size, but, in reality, shot a different one.

[perazzimx14]

Take it to a gun shop and have them mic the barrel and then the tighest part of the choke. Subtract the two #'s and this will give you the choke "constriction".

What is considered a full choke in one gun may be a modified choke in another gun. Actually the terms for choke tubes like full, modified and improved are totally meaning less unless you have the bore /choke diameters and compare the two.

Heres how it all plays out:

A true 12 gauge barrel will measure .729 thousandths of an inch the choke may measure .700 thousandths of an inch. At this point you have a constriction of .029 thousandth of an inch or a somewhat "full choke". Heres the rub! Say the previous owner had the barrel back bored to .800 but let the choke alone. You now have a barrel that has a bore diameter of .800 and a choke with a diameter of .700. Your constriction is now .100 thousandths of an inch or super, super full. Also keep in mind that barrel to barrel there is an allowable tolerance of diameter. So each barrel will have a slightly bigger or smaller bore diameter.

Basically you need the two measurements from the bore and the choke to give you a proper answer.

[BigV]

For a quick down and dirty check to find out if it's a full choke.
Try putting a dime into the end of the barrel. If it does not fit inside the barrel then it's a full choke.

[tote4570]

The dime did not fit. Thanks

[Nnobby45]

For a quick down and dirty check to find out if it's a full choke.
Try putting a dime into the end of the barrel. If it does not fit inside the barrel then it's a full choke.

Sorry Big. That's part truth and part myth. The real choke is determined by the difference between inside bore diameter and diameter at the muzzle-- expressed in points of constriction measured in thousandths.

The diameter of the bore at the muzzle is standard throughout the industry. The inside bore diameter is not as consistent in the barrel reaming process. Dime doesn't fit could be modified or full, or does fit could be anywhere's from full to IC.

Or the dime may not fit and the bbl. could shoot full, and perpetuate the myth even though it doesn't work that way all the time.


PerazziIMX14 explained it well. A 12 gage bore could vary from .729 or less to .735 or more. Add on variations in actual choke diameters that are marked the same and .............well you get the picture.


During manufacturing, they can't measure each inside bbl. diameter and then custom make the choke to get the right constriction. The interchangeable choke systems allow you to dial in the choke you want.

Only true way to truly varify your choke is to pattern at 40 yds. in 30" circle and figure the % shot in the circle. Even so, patterns can vary with different loads.

Choke is stamped on the barrel, as mentioned. Look up near the receiver. There's a reasonable chance it will shoot as advertised.

Might be the newer barrels are made by a more precise process and shoot closer to what's stammped on the barrel.

[BigV]

For a quick down and dirty check to find out if it's a full choke.
Try putting a dime into the end of the barrel. If it does not fit inside the barrel then it's a full choke.

As I stated above, for a quick down and dirty check, use a dime.
No science here, but just for s#its and giggles I checked some of my choke tubes to see if this unscientific method still holds true.

I checked my Browning invector tubes and a dime would not fit into the end of the Full Choke, but fit inside both the Mod and the IC tubes.
I then checked my Remington tubes and found the same to be true.
Lastly I checked the choke tubes on my Benelli and guess what...
Yep, the dime would not fit into the full choke tube, but fit inside both the Mod and the IC tubes.


So, again for a quick down and dirty check, use a dime. If it doesn't fit, then you have a full choke!

[Nnobby45]

I checked my Browning invector tubes and a dime would not fit into the end of the Full Choke, but fit inside both the Mod and the IC tubes.
I then checked my Remington tubes and found the same to be true.
Lastly I checked the choke tubes on my Benelli and guess what...
Yep, the dime would not fit into the full choke tube, but fit inside both the Mod and the IC tubes.


So, again for a quick down and dirty check, use a dime. If it doesn't fit, then you have a full choke!

Well, looks like you checked everything---except actually varifying on paper that the chokes shoot as advertised.

Down and dirty, basic check? OK, I'll go with that. But as stated, the industry standard for choke diameters is pretty uniform. The inside diameter of barrels is where variations occur. You can have an inside barrel diameter of .727 with the same choke in which the dime won't fit, and you have a modified choke instead of full ...........that's because the choke is determined by the difference.........oh, never mind, that's been pointed out, already.

In my younger days, I had a Ted Williams Sears 20 gauge, with adjustable choke --remember the old Pollychoke?, and I never patterned it, and never took it off modified. Worked fine for quite a few years.