Chokes 101....


Dave McCracken
May 15, 2003, 07:06 AM
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


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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May 15, 2003, 07:32 AM
Good post Dave.

Chokes can really get confusing, some really get worked up about it. I agree with the Cyl not getting the credit it deserves.

Sometimes too much knowledge is dangerous, meaning we caught up in something too much. The important stuff gets overlooked. I worked with a new shooter whom would not pattern his gun. He was afraid to actually know :confused: . 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.

Brister said " its a matter of bore not choke". You and I Dave agree gun fit, pattern boards, proper loads...practice makes a bigger difference than obsessing over some things.

Even the old "Cutts" if fitted to POA /POI worked. Still think a Cutts is great to rattle the concentration of fellow squad members though

May 15, 2003, 07:47 AM
Good post, Dave. Thanks for the information. I need to pattern my guns, too. :o

May 15, 2003, 09:05 AM
Excellent post,

As you said it boils down to the "P" word. Patterning is such a pain for me, I don't do it often. But, that's why I'm resistant to change "known" loads and use very few chokes.

I am waiting for someone to invent some "screen" you shoot into that instantly counts the pellets and gives you percentages, POI, etc. I'd pay for that service. Isn't that lazy!

I suspect if one were to do a lot of patterning, with different chokes and ammo combinations, there would be a lot less choke tubes bought. Particularly, the chokes that are inbetween the common designations.

Interestingly, I have read some of the best FITASC/Sporting shooters use fixed chokes and vary their ammo a bit.

May 15, 2003, 09:15 AM
And a hearty AMEN BROTHER!! Sing it Dave!!!

This is the gospel truth about chokes.

I will still admit being a choke junkie at one time, I have over 30 of the dang things in 3 different types. These days I use: IC for everything clay target except trap beyond 16 yards, and it is excessively tight for most targets even with 1oz loads. Trap from yardage I use a Light Full/IM, it is plenty from even the back fence with 1oz loads. For hunting I use Light Full/IM and a Full, in the 2 holer I use IC and Full. A 12ga with good shells can be the death ray on birds at ranges most would not believe using a tight choke. Basically I use 3 chokes, and could easily get by with 2. I can shoot repectably with only a Full on anything I want to shoot, and have done so. My guns with fixed full chokes still see plenty of clay targets, so don't feel under-equipped if you have a Full choked gun. Skeet especially is a hoot with Full chokes.

Chokes and guns are ALL individuals. They must be shot together in combinations on the pattern board before you will know what you have. What the guys at the club swear is the best ever may shoot like crap in your gun, I have seen it before. Find out what works in YOUR gun. Your abilities will also play a part in selection, tighter chokes make you work harder in practice, and your scores will show it come tournament time.

Dave McCracken
May 15, 2003, 10:05 AM
Thanks, folks. Looks like I'm not the only one with some thoughts on this.

I could get by with a Cylinder tube and a IM or Full if I had to. Luckily, I don't have to. I think I could screw in a LM (.015") tube on a 5 stand course, stuff some trap grade 7 1/2s in one pocket and some 8 1/2s in the other and not embarrass myself too badly. That is, as long as I kept my head on the stock and didn't stop my swing.Again, software is more crucial than the hardware.

H, Skeet with a Full choke? My, you do like a challenge. Does sounds like fun though. Good for deflating egos, just like opening day of dove season.

45auto, if you run across one of those screens, let me know. A very fine grid of low powered lazers could work, but costs would be high.

May 15, 2003, 12:10 PM
I doubt I'll come across one, but there may be a middle aged, now retired entrepreneur, that has made several fortunes, bored to tears and an avid shooter. Unfortunately, that's not me!

Set the "invention" up at shoots(sporting clays in particular) and charge $5.00 a shot.
It would be like trying to eat one potato chip.
The biggest problem would be the line up of shooters as each one tries 10 different choke tubes and ammo combinations.

Dream on!!

Dave McCracken
May 15, 2003, 01:55 PM
Thanks for the chuckle. I'd be in line myself!!

May 15, 2003, 11:51 PM
Find out what works in YOUR gun.

That's the key and the only way to find out is at the patterning board.

My rule of thumb on chokes is cylinder for targets out to 25 yards and add one POC for each additional yard. Skeet chokes out to 30 yards, IC for 35, 45 yards for modified and so on.

Most clay courses can be shot with IC or LM. I shoot Mod for 16 yard trap and IM for handicap.

But the more I shoot, the more I like LM. It's my usual choke if I don't want to change tubes during a round. I've been playing with some 7/8 ounce International 12 gauge loads lately. They are very fast with very hard shot and with the LM I can reach out and break distance birds and don't feel I am missing close targets.


Dave McCracken
May 16, 2003, 05:58 AM
International trap refutes the More Is Better bunch. Less than 7/8 oz on targets moving 80 MPH and at more varied angles.

Ammo is so much better now that some older shotguns like the Model 12 are oft overchoked. It's hard to make a case for chokes past IM (.025) except for turkey loads.

Dave R
May 16, 2003, 12:36 PM
Agreed that fewer is better. All my shotguns have two chokes. Near and far. Labels on the tubes may say something else...

And my ol' SXS has the old fashioned kind, where the chokes are actually built into the barrel. You never lose 'em that way.

And my 870 patterns 00 buck tighter with a Mod choke than with a full choke, proving once again that Dave is right--its all individual and patterning is the only way to know.

My 870 also shoots _nearly_ the same pattern in steel BBs with either Mod or full at 40 yards. So the ducks apparently won't care which I choose.

Dave McCracken
May 16, 2003, 07:45 PM
With 00,Modified oft is a bit too tight,actually.
Smaller buck like #1 usually works in Modified, tho of course, YMMV. A long forcing cone does help.

There's no substitute for patterning, and really little reason not to.

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