Understanding Shotgun Chokes

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PostPosted: Tue Sep 13, 2011 8:50 pm
Lots of good info here Shooter, Thank You!!!
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PostPosted: Wed Sep 14, 2011 1:53 am
Some choke makers list their constrictions in micrometers...here's a list to break the down:

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Micrometers..................Inches..................American Name

0.................................... .000......................... Cylinder
127................................ .005......................... Skeet
254................................ .010......................... Improved Cylinder
381..................................015......................... Light Modified
508................................ .020......................... Modified
635................................ .025......................... Improved Modified
762................................ .030......................... Light Full
889................................ .035..........................Full
1143.............................. .045......................... Extra Full
1270.............................. .055......................... Super Full

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.410
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PostPosted: Wed Sep 14, 2011 3:27 pm
The choke stamped on your barrel gives you a general idea what to expect but the only way to know for sure what your gun/choke/load combination will do is to put it on paper. Use the shotshell you intend to hunt with and pattern it at the distance that most of your shots come at. Changing only the shotshell can change the pattern enough to make a difference.
Rex
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PostPosted: Thu Sep 15, 2011 10:01 am
SHOOTER13 wrote:==================================================================

The floor is open to thoughts, additions, diversions, detractions and other comments... 8-)

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You're most welcome,

We could probably fill this forum with reems of data and theory. Amazing how complicated it is to throw a bunch of pellets downrange.
--Jim
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PostPosted: Thu Sep 15, 2011 10:04 am
Nickel and copper plated shot will always throw the tightest patterns with all other things being equal.
That is why I like the Fiocchi 28 gauge with the nickel plated shot. Another factor you can use to insure a tighter pattern is to buffer the shot. WInchester did this with their Super X shells with the Grex buffering, which was just powdered plastic. I have heard some shooters actually using flour, but I sure as heck wouldn't want to put flour through my reloader.
--Jim
PostPosted: Fri Sep 16, 2011 11:28 am
ravengunsmith wrote : "I have heard some shooters actually using flour, but I sure as heck wouldn't want to put flour through my reloader."

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Not unless I was making bread... ;)

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PostPosted: Mon Sep 19, 2011 3:29 am
SHOOTER13 wrote:ravengunsmith wrote : "I have heard some shooters actually using flour, but I sure as heck wouldn't want to put flour through my reloader."

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Not unless I was making bread... ;)

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I got that from a trap shooter. Some of those guys are truly maniacs. But that is OK, they do help my cash flow.
--Jim
PostPosted: Mon Sep 26, 2011 8:16 pm
This chart will give an idea of what choke to use at what yardage for sporting clays... with the caveat that ammo, intended target, angle of presentation ( front, back, side ) also weigh in on the equation...

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Image

Red - Pattern too small | Yellow - small but usable | Green - Optimal Pattern ===========================================================

Choke Tube Selection:

Choke tube selection is a confusing issue amongst a lot of shotgunners but one that is easily explained.

The real reason you want the right choke is to be able to place at least 70% of the shot in a 30" circle at 40 yards... the minimum / maximum pattern kill zone... meaning the pattern will cleanly kill anything in this circular zone.

Selecting the correct choke tube is nothing more than moving that same exact pattern to different yardages. In other words... if you want to shoot at a target 20 yards away then select a choke tube that gives you 70% of the pattern in a 30" circle at 20 yards...same if shooting at a target that is 45 yards away, select a choke tube that will give you 70% of the pattern in a 30" circle at 45 yards.

Extra Full Choke: ...................delivers a 70% pattern at 45 Yards.
Full Choke: ............................delivers a 70% pattern at 40 yards.
Modified Choke: ....................delivers a 70% pattern at 35 yards.
Improved Cylinder Choke: ....delivers a 70% pattern at 30 yards.
Cylinder Choke: ....................delivers a 70% pattern at 25 Yards.

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PostPosted: Wed Sep 28, 2011 1:27 pm
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From a 1961 Winchester catalog...

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Image

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**Thanks to GUNNER_D of the Winchester Owners Forum for this scan**

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PostPosted: Wed Sep 28, 2011 1:31 pm
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1961 Winchester Catalog...
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Image


===================================================

**Thanks to GUNNER_D of the Winchester Owners Forum for this scan**

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PostPosted: Wed Sep 28, 2011 1:34 pm
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1961 Winchester Catalog...
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Image


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**Thanks to GUNNER_D of the Winchester Owners Forum for this scan**

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.270 WIN
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PostPosted: Tue Oct 25, 2011 7:09 pm
Great post guys, I think that we also need to mention (I don't think it has been said) that while the markings on the choke and the barrel are a good rough guide, they are not infallible. Not all barrels are standard bore diameter, and each manufacturer has different ideas of what constitutes a specified choke. I once had a Beretta 12 ga that had such a small bore diameter that a skeet choke was literally cyl. bore. You had to use one choke constriction tighter to get the desired choke.

Also different shells, different wads, and different powders affect the degree of choke. Change one component in the shell and you have changed your pattern. It has been my experience that Federal ammo tightens patterns in ever shotgun that I have patterened it in. Likewise Remington ammo tends to pattern what the constriction actually is. You MUST pattern each shotgun with the ammo you intend to use at the distances that you intend to shoot if you are to have any idea of what is going on out there at range.

Case in point, my dad has a Remington Sportsman 58 12 ga. He bought a new barrel for it marked imp. cyl. We patterened with Federal shells and got a great modified pattern. We patterned with similar Remington shells (same shot size) and got a good imp. cyl. pattern. You have to pattern!

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PostPosted: Sat Jan 14, 2012 7:57 pm
Shooter, that is one great page you posted, thanks for sharing it!!
--Jim
PostPosted: Sat Jan 14, 2012 9:41 pm
The Colonel is absolutely correct...

...and thanks ravengunsmith !!
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PostPosted: Sun Jan 15, 2012 8:22 am
SHOOTER13 wrote:The Colonel is absolutely correct...

...and thanks ravengunsmith !!



You are very welcome shooter! And I will second that. Most people think a shotgun is a "spray and pray" type of firearm, but when you consider the powder charge, the type of powder, the primer, the wad, the size and the hardness of the shot, you realize that a shotgun pattern is one of the most complex things in all of the world of firearms. Even something as simple as using a different primer can alter performance.
That is why two boxes of shells, both labeled the same from different manufacturers can have such drastically different performance. You don't buy a new pistol or rifle and not check out how it shoots, you need to do exactly the same thing with your shotgun. When I consider all of the factors and parts that go into making a shotgun shell, I am amazing that I can hit anything at all.
--Jim

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PostPosted: Mon Jan 23, 2012 7:49 pm
Ain't that the truth!

.410
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PostPosted: Fri Mar 23, 2012 11:05 am
Well guys I must admit I must be doing something wrong. In over 50 years of shotgunning and numerous shotguns I have never patterned a gun. Sometimes I have 3 different brands and loads of shells in the gun. Doesn't seem to make a difference. The bird flushes, the gun goes bang, the bird goes down. When I miss it's my fault, not my gun or the ammo. I know what I did wrong. Usually not enought lead. In recent years I have gone to using only a modified choke. Works for me.
T.W.K.
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PostPosted: Sun Mar 25, 2012 12:45 pm
BC, you remind of alot of my uncle. He never patterned his Model 12's but he knew those guns so well that he instinctively understood how each gun would pattern. He knew the spread at just about any distance. He also knew the drop of any slug when he went deer hunting. My guess is that you know you guns so well, you do too. Patterning removes the learning curve and the time it take for you to know how your gun performs.
--Jim

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PostPosted: Sun Mar 25, 2012 7:12 pm
When I shoot at a bird I like to shoot low and catch the bird with the top edge of the pattern. 5 to 7 pellets will do the trick. I have seen many 1,2 and 3 pellet kills. My job is to put the bird on the ground so my dogs can have the fun of retrieving it. I have hunted with guys who use extra heavy duty magnum loads etc. When they hit a bird its just a puff of feathers and 2 wing tips. I like to have a nice bird to put on the plate.
T.W.K.
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