Shotgun Choke Question

[1075tech]

Picked up a 1963 Beretta O/U. Fixed chokes. I'm trying to determine what the chokes are.

They used "stars" to denote the choke. The barrels are marked with 3 and 4 stars respectively. This should equate to modified over improved cylinder.



However, the "chamber" is marked with 2 and 3 stars. This would equate to improved modified over modified.



Any ideas?

 

[LMS]

looks like you're going to have to just measure the diameter at the end to know for sure.

 

[PutnamCharlie]

From another post so not stating fact.
* = Full (sometimes marked as "choke)
** = Improved Modifed (3/4)
***= Modifed (1/2)
****= IC (1/4)
*****= Skeet

 

[LMS]

@PutnamCharlie , not sure that helps the OP since he has conflicting markings.

 

[PutnamCharlie]

True sorry.

 

[Acer-m14]

why cant they just stamp skeet on the gun barrels .. like my Ithaca skb o/u has and not stars ... lol ..

 

[1075tech]

why cant they just stamp skeet on the gun barrels .. like my Ithaca skb o/u has and not stars ... lol ..

Apparently 60 years ago the Italians thought it was cool to use "codes".

Figuring out the date was interesting as well. XVIII. = 18 which = 1963. The Roman numerals are the number of years after the end of WWII in 1945. Pre-war is even more interesting as the date code corresponds with the year of Mussolini's reign.

 

[togmaster]

It has to do with the size of the meatballs in mama's gravy.

 

[1075tech]

I used the current industry standard of .615" for the bore of a 20 gauge. Then I measured the ID of the muzzle. Figured the difference as the bore restriction. Cross referenced some charts online and came up with chokes of IM/M. Apparently this was one of the options for the 26" barrel

 

[SmallGameAddict]

I used the current industry standard of .615" for the bore of a 20 gauge. Then I measured the ID of the muzzle. Figured the difference as the bore restriction. Cross referenced some charts online and came up with chokes of IM/M. Apparently this was one of the options for the 26" barrel

A point or two for your consideration...

Many Italian (and Continental) shotguns are metric therefore have bore sizes that differ from American, for example 12 gauge US standard about .730", Italian .725"

My Benelli 20 gauge has a bore diameter of .625.

I'd suggest purchasing an inside micrometer to measure both bore diameter and muzzle exit diameter to be sure.

Failing that, enlist the services of a qualified gunsmith, and have him measure for you. While he's at it measure the chamber length, or check to see if the barrel is marked 65 or 70 somewhere.

Failing that, pattern each barrel with a standard target load for the chamber length, 65mm = 2-1/2" chamber, 70mm = 2-3/4". A standard target load for 2-3/4" being 7/8 Oz. of lead #7-1/2 or 8 shot at about 1200 fps (2-1/2 dram equivalent) and figure out the pattern percentages.

OR pattern the load you're going to shoot and figure out the pattern percentages, cuz with that particular load that's the choke no matter what is stamped on the barrel.

Hope this helps.

 

[1075tech]

A point or two for your consideration...

Many Italian (and Continental) shotguns are metric therefore have bore sizes that differ from American, for example 12 gauge US standard about .730", Italian .725"

My Benelli 20 gauge has a bore diameter of .625.

I'd suggest purchasing an inside micrometer to measure both bore diameter and muzzle exit diameter to be sure.

Failing that, enlist the services of a qualified gunsmith, and have him measure for you. While he's at it measure the chamber length, or check to see if the barrel is marked 65 or 70 somewhere.

Failing that, pattern each barrel with a standard target load for the chamber length, 65mm = 2-1/2" chamber, 70mm = 2-3/4". A standard target load for 2-3/4" being 7/8 Oz. of lead #7-1/2 or 8 shot at about 1200 fps (2-1/2 dram equivalent) and figure out the pattern percentages.

OR pattern the load you're going to shoot and figure out the pattern percentages, cuz with that particular load that's the choke no matter what is stamped on the barrel.

Hope this helps.

Seems like most major European countries had their own standards. English is different yet.

I measured the chambers the best I could. Chambers appear to be 2¾. No other numbers anywhere that I can find.

For chokes, it was recommended to measure the ID of the barrel 4" from the muzzle and at the muzzle. The difference would be the amount of constriction and therefore your choke.

My redneck way did match the barrel markings. I'm not sure what to make of the chamber markings.

I also measured the OD of the barrel and then the thickness of the barrel wall to get an ID and came up with similar numbers

 

[SmallGameAddict]

Well, funny thing about shotguns is when it comes to most "standards" there aren't many.

You've done quite a bit already. If it was mine I'd search online for a digital copy of the owners manual, and nose around on some forums.

You're prob on the right track with 3 stars = Mod and 2 stars = Improved Mod.

Although popular in Europe, shame that Improved Modified isn't a more popular choke in the US. I think it's great for late season pheasant in a single barrel gun, and for the second barrel in a double like yours.

 

[SmallGameAddict]

Found this link:

Choke Tubes for Beretta Shotguns

Shop Beretta choke tubes for shotguns. Explore our selection of high-performance shotgun accessories online today!

www.beretta.com

Scroll to bottom

Although the data presented by Beretta is applicable to their choke tube systems, one could reasonably conclude that they have use the same system of "stars" to mark the barrel with the nominal choke constriction of each barrel for some time, and simply carried these designations over from their fixed chokes to their choke tubes.

 

[1075tech]

XFULL TURKEY No Color
Full * F 1 White
Light Full LF Gray
Improved Modified ** IM 2 Black
Modified *** M 3 Green
Light Modified LM Orange
Improved Cylinder **** IC 4 Yellow
Skeet USA SK USA Purple
Skeet SK Red
Cylinder ***** CYL 5 Blue
SP - ALL STEEL SHOT COMPATABLE CHOKE TUBES

Therein is part of the question. The chambers are marked with 2 and 3 stars whereas the barrels are marked with 3 and 4 stars.

I'll take it to the shop tomorrow maybe if he has a way to measure the ID of the barrels

 

[SmallGameAddict]

XFULL TURKEY No Color
Full * F 1 White
Light Full LF Gray
Improved Modified ** IM 2 Black
Modified *** M 3 Green
Light Modified LM Orange
Improved Cylinder **** IC 4 Yellow
Skeet USA SK USA Purple
Skeet SK Red
Cylinder ***** CYL 5 Blue
SP - ALL STEEL SHOT COMPATABLE CHOKE TUBES

Therein is part of the question. The chambers are marked with 2 and 3 stars whereas the barrels are marked with 3 and 4 stars.

I'll take it to the shop tomorrow maybe if he has a way to measure the ID of the barrels

That is curious

 

[spat]

XFULL TURKEY No Color
Full * F 1 White
Light Full LF Gray
Improved Modified ** IM 2 Black
Modified *** M 3 Green
Light Modified LM Orange
Improved Cylinder **** IC 4 Yellow
Skeet USA SK USA Purple
Skeet SK Red
Cylinder ***** CYL 5 Blue
SP - ALL STEEL SHOT COMPATABLE CHOKE TUBES

Therein is part of the question. The chambers are marked with 2 and 3 stars whereas the barrels are marked with 3 and 4 stars.

I'll take it to the shop tomorrow maybe if he has a way to measure the ID of the barrels

Might be able to slug the barrel.

You force a soft slug through with a rod, then measure the diameter of the slug.

 

[kev74]

Might be able to slug the barrel.

You force a soft slug through with a rod, then measure the diameter of the slug.

I wouldn't do that with a shotgun barrel. Way too thin!


Maybe the original owner put a star on there every time he won a round???

 

[spat]

I wouldn't do that with a shotgun barrel. Way too thin!


Maybe the original owner put a star on there every time he won a round???

Probably don't want to use a solid lead slug, but there are other things you could use. A hollow slug might work (or just drill a 1/2" hole in a solid one to relieve some of the pressure).

Sorely a shotgun barrel is plenty strong enough for that.

The best would be a ball of plastigauge, but I'm not sure if they make such a thing.

I bet there is some modeling clay like product that would work well.

I don't think this requires *that* much precision.

I have a cheap set of these, and that's probably all I would use.

Telescoping Gauge Set, 6 Piece

Amazing deals on this Telescoping Gauge Set 6Pc at Harbor Freight. Quality tools & low prices.

www.harborfreight.com