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20b choke question


bicykillgaz
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Hi gents,

I've just got a new o/u 20b and stuck 1/2 &1/4 in it but then I got out in the woods alone to test it and got thinking, im using 28g 6s through the 20b with 1/4 & 1/2 but if I was using a 12g 28g load I'd probably use 1/4 & 1/2 which means the 20b is chucking the same amount of lead in a lot tighter pattern.

 

It got me wondering if when people go from 12 to 20 do you open your chokes up to 1/4 & cyl or go with the tighter pattern? :hmm:

 

Atb Gary

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No matter what bore, the spread for any given degree of choke remains the same.

 

 

So with a 20 and 12 at 25, 30 and 40 yards the patterns are the same size? :hmm: I understand that the angles which the shot exits the barrel witll be the same but surely the pattern sizes differ? I thought you had a larger killzone with a 12 than a 20

Edited by bicykillgaz
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No matter what bore, the spread for any given degree of choke remains the same.

I've pondered this for a while but also assumed a smaller diameter (20b) would give a tighter pattern than a larger diameter (12b). So basically shooting a 20b with cylinder would be like a 12b with full (perhaps):hmm: ? I'd love to get my head round the physics so a more in-depth explanation would be appreciated :good:

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:stupid:

 

only diff is a longer shot string on the 20, due to the length of the column of shot.

leave em at 1/4 + 1/2 mate you cant go wrong unless they are very long birds.

 

 

Seemed to work well enough on the squirrel I bagged :good:

 

I've pondered this for a while but also assumed a smaller diameter (20b) would give a tighter pattern than a larger diameter (12b). So basically shooting a 20b with cylinder would be like a 12b with full (perhaps):hmm: ? I'd love to get my head round the physics so a more in-depth explanation would be appreciated :good:

 

 

That's what I though only you wrote it better :blush:

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probably impossible to tell in real life what the difference is. choke , i think is only a measure of constriction in the end of the barrel.

and given that one shell type/brand will pattern different to another type/brand, the only solution is to get in the woods with some paper

and give it a go gary.

 

Percentage Of Shot Inside 30″ Circle

CHOKE 20 Yds 30 Yds 40 yds

Cylinder 80% 60% 40%

Skeet 92% 72% 50%

Improved Cylinder 100% 77% 55%

Modified 100% 83% 60%

Improved Modified 100% 91% 65%

Full 100% 100% 70%

 

use these charts to work out what you are actually getting from a particular shell/choke combination.

 

SHOT SIZE LEAD/ STEEL

8 585 - – -

7 1/2 410 - – -

6 225 316

5 170 243

4 135 191

 

count per ounce of shot.

 

good luck counting all those little holes :lol:

 

stu

Edited by stu nesling
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probably impossible to tell in real life what the difference is. choke , i think is only a measure of constriction in the end of the barrel.

and given that one shell type/brand will pattern different to another type/brand, the only solution is to get in the woods with some paper

and give it a go gary.

 

Percentage Of Shot Inside 30″ Circle

CHOKE 20 Yds 30 Yds 40 yds

Cylinder 80% 60% 40%

Skeet 92% 72% 50%

Improved Cylinder 100% 77% 55%

Modified 100% 83% 60%

Improved Modified 100% 91% 65%

Full 100% 100% 70%

 

use these charts to work out what you are actually getting from a particular shell/choke combination.

 

SHOT SIZE LEAD/ STEEL

8 585 - – -

7 1/2 410 - – -

6 225 316

5 170 243

4 135 191

 

count per ounce of shot.

 

good luck counting all those little holes :lol:

 

stu

 

 

 

I think I'll take yours and wymberleys word for it, is that shot percentage/distance chart generic for all gauges then?

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as far as i know, yes. as it uses the pellet count in the circle divided by the number of pellets in the shell x 100to give you the %.

its a fixed equation that can be applied to any bore.

 

dont look into it too deeply gaz, if the squizzers die, its right. :lol:

 

stu

Edited by stu nesling
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as far as i know, yes. as it uses the pellet count in the circle divided by the number of pellets in the shell x 100to give you the %.

its a fixed equation that can be applied to any bore.

 

dont look into it too deeply gaz, if the squizzers die, its right. :lol:

 

stu

 

 

It was quiet not much about and my mind started wondering, I just assumed smaller barrel meant smaller kill zone so if it was the same load it would just be a more dense tighter pattern.

 

The squirrel definitely died shame I wasn't quick enough to get his mate on the branch above too.

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My remmy 870 came with a 1/2 choke tube. I dismissed it and ordered a 1/4 .I recently put the 1/2 back in and seemed to d better with it!

 

I am now thinking all I may of done is use the chokes to suit the shell. I am of the notion it can be foolish to trust a chart.

 

Only a test will satisfy.

 

U.

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There's always confusion about this just as there's a train of thought that thinks the effective range of, say, a 410 is less than, say, a 12 bore because the velocity of similar sized pellets is less in the smaller bore.

 

Choke is a performance, not a measurement. The measurements of the physical restrictions in the barrel vary with each bore and are designed to give the one range/pattern spread with which we are all familiar.

 

PS The lead pellet sizes given on this thread are not British.

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Choke is a performance, not a measurement. The measurements of the physical restrictions in the barrel vary with each bore and are designed to give the one range/pattern spread with which we are all familiar.

 

Choke is a measurement, but also a term which instigates confusion. No mater what choke, skeet or extra full if you are on the target with the correct size and load of pellet, it's a hit.

 

Try pattern testing for real and not with percentages etc and you will have a surprise or two.

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Hi gents,

I've just got a new o/u 20b and stuck 1/2 &1/4 in it but then I got out in the woods alone to test it and got thinking, im using 28g 6s through the 20b with 1/4 & 1/2 but if I was using a 12g 28g load I'd probably use 1/4 & 1/2 which means the 20b is chucking the same amount of lead in a lot tighter pattern.

 

It got me wondering if when people go from 12 to 20 do you open your chokes up to 1/4 & cyl or go with the tighter pattern? :hmm:

 

Atb Gary

hello i use a browning 20g an i always use cyl an 1/4 or 1/2 for pigeon decoyin an pheasant an inland duck shooting.i use 28gram felt wad 6,s and for duck 24gram steel.an its my favorite set up,better than my browning 12,an my beretta 12s/a cos its so light an pointable an easy to carry all day.regards an good hunting.john.

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Choke is a performance, not a measurement. The measurements of the physical restrictions in the barrel vary with each bore and are designed to give the one range/pattern spread with which we are all familiar.

 

Choke is a measurement, but also a term which instigates confusion. No mater what choke, skeet or extra full if you are on the target with the correct size and load of pellet, it's a hit.

 

Try pattern testing for real and not with percentages etc and you will have a surprise or two.

 

I've pattern tested a few in my time. The OP was shooting live quarry and by the sound of you shoot clays. For you it may well be a hit; but more critically for the live quarry guys, is it a clean kill? Think on.

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