View Full Version : choke patterns

November 5, 1999, 11:09 PM
I was wondering can some one explane or send me a chart on what the diffrent patters look like with the diffrent chokes?

improved choke
thanks for your helps

k in AR
November 6, 1999, 12:21 PM
the idea of changable chokes is to get a certain percentage of pellets in a 30" (or whatever size) circle at a given range. The thighter the choke the father away it will hold the pattern.
(I think I have been about as clear as mud....)

Anyway, guess what: there is no real manufactures standards here. Every mfg's choke is somewhat different and may not even shoot to the same point of aim. Thus, if you want to really know about your chokes, you must "pattern" them.
(which is another subject all together)

Big Bunny
November 8, 1999, 04:47 PM
Crikey!! You have opened SOME subject!!

Suggest you pattern your usual cartridge and choke on butcher's paper at 35m(draw circle afterwards!).
The size of the shot is also critical(can't help there- you have different sizes to British).
Perhaps-A VERY ROUGH rule of thumb could be..45m-full..35m-threequarters choke..25m-half..20m (and under)-cylinder or IC... but it also depends upon the size of the game hunted as well.
Draw a circle of the game's vital area(exclude wings if wing-shooting) (NB after patterning... it is not an accuracy test !) and then aim for 5 hits with small shot or 3 with heavier types.

Burn some powder and pattern your gun, if you do it will pay you well, either on the range or hunting.
There are many books on this subject.

Good luck - and pad that shoulder !

***Big Bunny***

November 8, 1999, 06:06 PM
High House, (Clay shooters pun)

Chokes really are very simple (Ha!), they are varying degrees of constriction at the end of the barrel which control the percentage of shot in the critical 'killing' area of your pattern at a given distance from the end of your barrel. There is no industry standard and different manufacturers use different constrictions for different chokes.

The most common designations of chokes is as follows:

Cylinder - there should be no constriction
Skeet - slight constriction only
Improved Cylinder - usually 1/4 of full constriction
Modified - usually 1/2 of full constriction
Improved Modified - usually 3/4 of full constriction
Full - Full Constriction
Extra Full - More constriction than Full

Another small spanner in the works is that every gun patterns every different cartridge type differently. Therefore, if you had two Remington 870's, they might need different types of ammo (not likely, but possible). These differences in pattern are usually not detectable to the shooter. The key is to find a cartridge that you are happy with. Follow Big Bunny's advice and check out what works well in your gun.

A major myth is that barrel length affects patterning at longer ranges. The difference between an 18in barrel and a 30in barrel is twelve inches. If they have the same choke, twelve inches is the only difference at any given range. Choke is key to effective shotgunning and if you have to err on the side of caution, go slightly tighter with your choke rather than more open.

For wildfowling, please use a full choke as clean kills are desirable. Please refrain from shooting at ranges over 45-50yds as you are more likely to wound your target than kill it.

For clays, you will seldom need anything tighter than improved modified (long sporting clay shots and ISSF Olympic Trench excepted) if you have a good patterning gun. Have Fun and try ISSF Skeet.

November 8, 1999, 08:43 PM
Thanks for all your info guys. I Have started to shoot alot of trap and skeet so all your info helped thanks agine.

Big Bunny
November 8, 1999, 09:02 PM
Beano, that was a good posting!

But I feel that barrel length does affect velocity and therefore pattern to a smaller extent perhaps, depending upon the particular cartridge/powder load, [and those of us who reload can tailor this factor into them for various guns using various powders and shot-loads/wads].
I have various shotguns in 12GA from 20" to 28" long and after playing around with my Chrony F1 I feel there is around a 80fps loss in velocity from one length to the other, (more in magnum 3"loads using W571.)
Small beer it maybe... but could be interesting to some members .

***Big Bunny***

November 9, 1999, 05:44 PM
12-Gauge using .730 inch as Standard bore l.D.

Cylinder -------- .730 -------- .000
Skeet-1 -------- .725 -------- .005
Improved-Cylinder -------- .720 -------- .010
Skeet-2 -------- .715 -------- .015
Modified -------- .710 -------- .020
Improved-Modified -------- .705 -------- .025
Maximum-Modified -------- .700 -------- .030
Full -------- .695 -------- .035
Xtra-Full -------- .690 -------- .040
Maximum-Full -------- .635 -------- .045

November 9, 1999, 11:30 PM
Agreed Big Bunny,

Didn't want to get too technical as the whole issue of velocity is another big one.

November 10, 1999, 04:44 AM
On a home defense shotgun what type of choke should be used?

Sorry if this is a dumb question I'm new to shotgunning.

November 11, 1999, 01:11 AM

If you're refering to an appartment as "home", then I don't think choke would be a factor.....at appartment range you'd be hard pressed to measure the difference in pattern size.

Having said that, an open ( cylinder or skeet ) will throw the larger shot pattern.

However, if you're defending a 150 acre farm, then a full choke will sufice for the shortest range, but will be much better for four legged predators at a range of say 50 yards or more.

For two legged predators, what is most effective is having the "predator" looking down the business end of TWO barrels, or to HEAR the shell being shucked and chambered by the slide-action or simi-auto.

With either of these techniques employed, you just may never have to fire a shot. ;)

Ralph in In.

November 11, 1999, 08:22 AM
Get a copy of Bob Brister's book "Shotgunning, the Art and the Science". Everything and I mean everything you might want to know about chokes and shotgun patterns can be found in this book. It is one of the few books that actually explains shot strings and how they work.

At most home defense distances the chokes are not given enough time to fully open up. The best chokes lie between Cylinder and Improved Cylinder. However, I would not want to be hit in the chest with a full choke at 10 yds!

Geoff Ross

Damn!...I need more practice!
Pi$$ off the left, register to vote.

November 11, 1999, 11:13 AM
good link: