Dave McCracken
Moderator In Memoriam
150 years ago or so,America was covered with moving shotgun targets.
Everything from Passenger Pigeon to Whooping Cranes was fair game. The trouble was, most of it selfishly insisted on flying well out of range of the equipment of the time. According to lore, a market gunner( An honorable profession then) named Fred Kimble messed around with a new 6 gauge barrel and found that if the muzzle was a little smaller than the bore, the shot stayed together better at longer ranges.This is called choke. The rest is history, and chokes are standard on nearly all shotguns nowadays. Recently, interchangeable choke tubes have become the rage, so one can have one barrel and a myriad of tubes to tailor the pattern to any mission.There's a downside there we'll get to later.
Definitions differ, but chokes are usually labelled by how much constriction there is, OR by the percentage of shot landing in a 30" circle when shot at 40 yards.
In 12 gauge, Cylinder(No choke) runs about the nominal .729" the bore is supposed to be. Improved Cylinder gives, in theory, about a 50% pattern at 40 yards and runs about .010" tighter. Sometimes the figure is expressed as Points Of Constriction or POC. One POC equals .001". It's the difference between the bore and choke diameters that determine constriction, not just fractions of inches.
Makers have their own scales,but in 12 gauge these are commonly found. There's 5 POC difference in each increment of choke.
Cylinder-0 POC
Skeet-5, sometimes a choke marked Skeet has NEGATIVE choke, meaning larger than bore diameter.
Improved Cylinder-10
Light Modified-15
Modified-20,should give 60% patterns @ 40 yards
Improved Modified-25
Light Full-30-70% patterns @ 40 Yards
Full-35
Extra/Super Full-40
OK, everyone got that?
Too bad, because it's meaningless.All it does is indicate probabilities.
Any discussion of pattern has to include load as well as choke.The twain are as interlocked as Yang and Yin.
Factorsthat affect patterns include shot size,hardness,roundness,polish, lubricity,quantity,velocity,acceleration,burn rate,air pressure, humidity, and whether the gunner is getting enough fiber. There's other factors, but you get the idea.
In a given shotgun with an unvarying load, a Skeet choke will give a more open pattern than a tighter choke. A Modified choke will give a more open pattern than Full, all else equal. As to how much, only patterning (The P word!) can tell.
Part of the irony of modern shotgunning is that the more and better chokes we have, the less we need them.
Great strides have been made in choke technology,and greater ones in ammo. The one piece plastic wad has made chokes unneeded for some shotgunning.
A Cylinder bore shotgun with a good trap load keeps an effective pattern out to 25 yards or so. With the best 1960s ammo,it would have been more like 20. With field loads of the time, maybe 15.
IOW,a Cylinder choked shotgun with proper ammo is effective for all skeet shots, most SC shots, and many hunting opportunities.Cylinder would be my choice for quail over good dogs, woodcock in the alders, etc, assuming proper ammo.
OTOH, I'd want something tighter for pass shooting, trap, turkey and so on. The right tube for the right job.
A hand is up at the back of the classroom.
"Now that we're totally confused,what choke tubes should one get for an all around shotgun?"....
This varies, of course, and I apologize for being vague. There's few certainties here. Most folks will do well with just three tubes, something open, something tight, and something in between.
Cylinder, Light Mod and Improved Mod(0, 15, and 25 POC) may be a good combination for your ammo of choice.
So might Skeet, Mod and Full.
I'd have at least 10 POC between for starters, one can adjust the pattern by altering those other factors listed above. Patterns neither open nor close incrementally,so test before use.
Of course, one could buy the whole set and endlessly change them. You'll score better by settling on a couple and concentrating on good form and technique.
And that downside....
Quite a few tubes will not shoot to the same point of impact as others in the set. And, on occasion the installation is a bit skewed, with the shot going off other than where it's supposed to.Again, TEST before use. and do not settle for "Close enough"....
Everything from Passenger Pigeon to Whooping Cranes was fair game. The trouble was, most of it selfishly insisted on flying well out of range of the equipment of the time. According to lore, a market gunner( An honorable profession then) named Fred Kimble messed around with a new 6 gauge barrel and found that if the muzzle was a little smaller than the bore, the shot stayed together better at longer ranges.This is called choke. The rest is history, and chokes are standard on nearly all shotguns nowadays. Recently, interchangeable choke tubes have become the rage, so one can have one barrel and a myriad of tubes to tailor the pattern to any mission.There's a downside there we'll get to later.
Definitions differ, but chokes are usually labelled by how much constriction there is, OR by the percentage of shot landing in a 30" circle when shot at 40 yards.
In 12 gauge, Cylinder(No choke) runs about the nominal .729" the bore is supposed to be. Improved Cylinder gives, in theory, about a 50% pattern at 40 yards and runs about .010" tighter. Sometimes the figure is expressed as Points Of Constriction or POC. One POC equals .001". It's the difference between the bore and choke diameters that determine constriction, not just fractions of inches.
Makers have their own scales,but in 12 gauge these are commonly found. There's 5 POC difference in each increment of choke.
Cylinder-0 POC
Skeet-5, sometimes a choke marked Skeet has NEGATIVE choke, meaning larger than bore diameter.
Improved Cylinder-10
Light Modified-15
Modified-20,should give 60% patterns @ 40 yards
Improved Modified-25
Light Full-30-70% patterns @ 40 Yards
Full-35
Extra/Super Full-40
OK, everyone got that?
Too bad, because it's meaningless.All it does is indicate probabilities.
Any discussion of pattern has to include load as well as choke.The twain are as interlocked as Yang and Yin.
Factorsthat affect patterns include shot size,hardness,roundness,polish, lubricity,quantity,velocity,acceleration,burn rate,air pressure, humidity, and whether the gunner is getting enough fiber. There's other factors, but you get the idea.
In a given shotgun with an unvarying load, a Skeet choke will give a more open pattern than a tighter choke. A Modified choke will give a more open pattern than Full, all else equal. As to how much, only patterning (The P word!) can tell.
Part of the irony of modern shotgunning is that the more and better chokes we have, the less we need them.
Great strides have been made in choke technology,and greater ones in ammo. The one piece plastic wad has made chokes unneeded for some shotgunning.
A Cylinder bore shotgun with a good trap load keeps an effective pattern out to 25 yards or so. With the best 1960s ammo,it would have been more like 20. With field loads of the time, maybe 15.
IOW,a Cylinder choked shotgun with proper ammo is effective for all skeet shots, most SC shots, and many hunting opportunities.Cylinder would be my choice for quail over good dogs, woodcock in the alders, etc, assuming proper ammo.
OTOH, I'd want something tighter for pass shooting, trap, turkey and so on. The right tube for the right job.
A hand is up at the back of the classroom.
"Now that we're totally confused,what choke tubes should one get for an all around shotgun?"....
This varies, of course, and I apologize for being vague. There's few certainties here. Most folks will do well with just three tubes, something open, something tight, and something in between.
Cylinder, Light Mod and Improved Mod(0, 15, and 25 POC) may be a good combination for your ammo of choice.
So might Skeet, Mod and Full.
I'd have at least 10 POC between for starters, one can adjust the pattern by altering those other factors listed above. Patterns neither open nor close incrementally,so test before use.
Of course, one could buy the whole set and endlessly change them. You'll score better by settling on a couple and concentrating on good form and technique.
And that downside....
Quite a few tubes will not shoot to the same point of impact as others in the set. And, on occasion the installation is a bit skewed, with the shot going off other than where it's supposed to.Again, TEST before use. and do not settle for "Close enough"....
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. I patterned his gun because I wanted to know. He obsessed about chokes, always changing. I finally lied to him about changing his choke and left the cyl choke in, he thought he had a Skeet 2, once he had (in his mind)" the right choke" he concentrated on the bird and not the gun he broke targets.