410 cartridges

[wymberley]

Although the 12 bore aspect is easy to explain, it is extraneous as the OP is talking 410. He is also talking about killing pigeon - as in dead. I happen to disagree with one part of the BASC pattern test procedure (which for our purposes here doesn't apply anyway, but does relate to your 140 - 150 figure). However, I do agree with their 6 pellet on average strike rate requirement deemed necessary to kill some 95% of the time - this naturally assumes and accurate shot - and which applies across the board irrespective of whatever calibre or load weight.

EDIT: PS forgot, we're also talking 6 shot.

Edited November 21, 2017 by wymberley

[neutron619]

36 minutes ago, wymberley said:

Although the 12 bore aspect is easy to explain, it is extraneous as the OP is talking 410. He is also talking about killing pigeon - as in dead. I happen to disagree with one part of the BASC pattern test procedure (which for our purposes here doesn't apply anyway, but does relate to your 140 - 150 figure). However, I do agree with their 6 pellet on average strike rate requirement deemed necessary to kill some 95% of the time - this naturally assumes and accurate shot - and which applies across the board irrespective of whatever calibre or load weight.

EDIT: PS forgot, we're also talking 6 shot.

I'm sorry - you've lost me.

My original point was intended to mean that, if you're having to resort to using a 20" circle (or smaller) to achieve an equivalent effective pattern density equal to XXX pellets in the standard 30" circle, then you are by default accepting a smaller effective pattern area.

If that's the case, then you need to shoot more accurately to a degree equivalent to the ratio between the "allowed for" effective pattern area and the area of the standard circle. If that's a 20" circle (ratio = approx. 0.44), then you need to be 124% (i.e. 1 / 0.44 - 100%) more accurate. For someone who just manages the 1-for-3 accepted standard, that's probably concerning.

[TIGHTCHOKE]

If we then limit our useful shooting to the maximum distance that a 20" circle would include the vast majority of the charge of pellets are we not seriously reducing the already limited range of the little gun?

 

[wymberley]

49 minutes ago, neutron619 said:

I'm sorry - you've lost me.

My original point was intended to mean that, if you're having to resort to using a 20" circle (or smaller) to achieve an equivalent effective pattern density equal to XXX pellets in the standard 30" circle, then you are by default accepting a smaller effective pattern area.

If that's the case, then you need to shoot more accurately to a degree equivalent to the ratio between the "allowed for" effective pattern area and the area of the standard circle. If that's a 20" circle (ratio = approx. 0.44), then you need to be 124% (i.e. 1 / 0.44 - 100%) more accurate. For someone who just manages the 1-for-3 accepted standard, that's probably concerning.

!st Para'.

You keep on about the 30" circle. Staying with No6 against pigeon then to effectively use the full 30" you'd need a 55g load and Full choke - a mini canon. Consequently your final phrase is valid.

2nd Para'.

Quite right. No one ever said it was easy. I'm not quite sure when talking about an accepted standard for decoying pigeon being 1-for3. I get annoyed if I drop below 1-for2 and given a good day, 2-for-3 makes me smile.

For our game 410 game shooters, please note that we're talking the relatively smaller pigeon here with 6s and obviously with plenty of energy at hand a lesser pattern density is perfectly acceptable for larger birds.

There's an old anglers saying regarding terminal tackle that applies equally well here - 'keep it simple'.

33 minutes ago, TIGHTCHOKE said:

If we then limit our useful shooting to the maximum distance that a 20" circle would include the vast majority of the charge of pellets are we not seriously reducing the already limited range of the little gun?

 

Of course, but only because we're talking 11g of 6s. Make that c20 of 7/7&1/2s and things change.

Edited November 21, 2017 by wymberley

[Walker570]

I successfully shoot partridge, just as quick and about the same size as pigeon with 18.5grs of #7s. If a pigeon happens to be foolish enough to pass within 40yrds after the first game birds have passed over the guns it will get the same treatment.  It is up to me to put that bird in the middle of the pattern.  My average this year is not as good as normal, just 2.8 to 1.  Being a 410 shooter I pick all of my cases and I mark every bird I kill AND make sure the pickers up are aware of the positions. Purely out of interest I have changed to the #2 chokes in the Yilditz from my normal full and full and cannot see any difference in results.  Finding the cartridge/choke combination which gives the best pattern is vitally important with any gauge but even more so with the 410.

I have been offered a couple of ideas for successful reloads and grateful for the offer, BUT the loads I have pattern very well indeed and the results in the field are first class so I will not be changing horses in mid stream so to speak.  The dire score of 2.8 - 1 is nothing to do with the cartridge

[neutron619]

42 minutes ago, wymberley said:

You keep on about the 30" circle. Staying with No6 against pigeon then to effectively use the full 30" you'd need a 55g load and Full choke - a mini canon. Consequently your final phrase is valid.

Sorry - you're going to have to explain this. You seem to be relying one some information that either I haven't noticed, you haven't connected for us or which doesn't appear on this thread. Why on earth would anyone need a 55g load and a full choke to shoot woodpigeons with #6? Mathematics aside, that's so far from reality that surely you should be questioning it yourself?

As for the rest, much of a muchness I'm afraid. If you have a load with sufficient density for a 30" circle, then it's effective over 30". The same is true for 20". I'm just not sure why anyone would choose to handicap themselves with a 20" effective pattern area when 30" is perfectly possible, even in the .410?

Edited November 21, 2017 by neutron619

[Stonepark]

Gents,

I think (and perhaps risking alienating everyone) perhaps the point being missed is that at 20 yards, whether 12 bore or 410 the pattern spread is 21 inches in diameter with half choke, therefore we need to look at the density of the pattern at this range. and consider that whether,  at 20yds range the 410 will kill with an adequate pattern with 11g of No6 versus  the 12 will 'mince' the target (to use an inaccurate but generic misunderstanding) with 32g of No6.

I would  argue that at no matter the range you need to be almost equally  as accurate with the point of aim whether 12 bore or 410, as whilst with half choke the range doubles from say 20 yds to 40 yds (100% increase), the pattern diameter increases from 21 to 45 (which is an increase of 115% but is not too dissimilar), however if you consider the core pattern (whether traditional 30 inches or 'hot' 20 inch core), you in reality have to be more accurate at range with the 12 than you would have to be for the 410 at close range.

 

 

[wymberley]

18 minutes ago, neutron619 said:

Sorry - you're going to have to explain this. You seem to be relying one some information that either I haven't noticed, you haven't connected for us or which doesn't appear on this thread. Why on earth would anyone need a 55g load and a full choke to shoot woodpigeons with #6? Mathematics aside, that's so far from reality that surely you should be questioning it yourself?

As for the rest, much of a muchness I'm afraid. If you have a load with sufficient density for a 30" circle, then it's effective over 30". The same is true for 20". I'm just not sure why anyone would choose to handicap themselves with a 20" effective pattern area when 30" is perfectly possible, even in the .410?

This.

Only if you're attempting to utilise the full 30" as said.

I know that you're a clever bloke so instead of writing  sufficient to bore many, just one word plus some figures which should help:

Gauss

Size: 44.4 and 55.6

Density; 41.4 and 28.6

[neutron619]

2 hours ago, wymberley said:

This.

Only if you're attempting to utilise the full 30" as said.

I know that you're a clever bloke so instead of writing  sufficient to bore many, just one word plus some figures which should help:

Gauss

Size: 44.4 and 55.6

Density; 41.4 and 28.6

I see where we're going with this and we've been round this route once before on another thread.

I'm afraid your numbers don't make what you're saying entirely clear to me, but, like last time, I'm guessing the confusion lies in the understanding of what the Normal distribution - a special case of the Gaussian distribution as you indicate - describes.

Briefly, I assume that you are:

• taking a Normal distribution of pellets (i.e. a standard pattern) of X density in a 30" circle
• finding the pellet count within a 20" circle inside that
• using that density to back-calculate the number of pellets required to achieve the same density or greater over a 30" circle?

If that's the case, then you are comparing the Normal pattern density in the first point with the linear density described by the second and then deriving a new Normal function from that linear density in the third. This is the mistake that most of the old literature and much of the new literature makes.

Many people correctly take the long-understood empirical conclusions that you need X pellets in the circle for some species and Y pellets in the circle for another which are broadly correct (within a range of opinion) and then misapply mathematics to the numbers to try and give them a grounding in "science".

The common failure of understanding is that the Normal distribution isn't a measurement of pattern density per se but is a function which describes it, meaning that the the first two points above describe two completely different pattern densities but one probability function specific to the gun, cartridge and choke. It is this probability function and not an absolute pattern density which is described by the historical, empirical need for Z pellets in the 30" circle for ABC species that used to be printed in the Eley handbook.

To be frank, most people do not have a strong grasp of probability distributions, but they do know how to count, so rather than publishing mu and sigma and letting people work it out for themselves, Eley and the industry standardized on a 30" circle and published the number for that instead. Unfortunately, that has led to the misunderstanding that one can simply take the number of pellets in the 30" circle, divide it by the 706 square inches in that circle to find the density per square inch, then multiply it by another number of square inches (e.g. 314) and call those densities equivalent. Linearly, they are, but functionally, they aren't.

To illustrate - imagine you cut out two circles, one 30" and one 20" and put them up for patterning together. You then fire the shot, take them down and count the 30" pattern finding that there are 200 pellet impacts on the circle. You do the ratio calculation and predict that there will be approximately 44% of the number of pellet impacts in the smaller circle, or 88. You then count the impacts in the 20" circle and find that, rather than 88 impacts, there are actually 110 - as your books will suggest to you. Confused, you count both plates again, but start with the 20" circle this time and do the inverse calculation: the 30" circle should contain 224% of the pellets of the 20" circle (or 246) - but hang on - it only has 200. What's wrong?

The same function gives different densities for different sizes of circle. The function describes the behaviour of gun, choke and cartridge. A function describes the pattern which puts 120, 140, 160 pellets in the 30" circle at given range. Ideally, the two align, or the former describes a function whose resultant at a given pattern diameter exceeds the resultant of the latter. Pattern density itself doesn't come into it.

 

Edited November 21, 2017 by neutron619

[wymberley]

Good heavens, what happened to "keep it simple"?

[neutron619]

21 minutes ago, wymberley said:

Good heavens, what happened to "keep it simple"?

Ok - let's try a quick and dirty example and then I'll leave it before the OP / mods try to assassinate me or shut down my account.

Scenario: you want 150 pellets in the 30" circle at any distance.

The linear density of that pattern, if you get it, will be 0.212 pellets per inch (150 in 706 square inches).

You look at your tables and find that that's equivalent to 109 pellets in a 20" circle, which is a linear pattern density of 0.346 pellets per inch (109 in 314 square inches).

Why? The reason for this change in linear density is the fact that the pattern is described by a probability function.

Take a look at this: http://onlinestatbook.com/2/calculators/normal_dist.html Use a mean of 0 and a standard deviation of 1 to keep things simple.

Let's say our 30" circle is "standard" and therefore equivalent to the range -1 to 1 on the probability scale. The probability of a pellet landing inside that range for the function illustrated is 0.6827. Now reduce the diameter of the circle by 33% to represent a 20" circle - equivalent to a range of -0.666 to 0.666 on that graph. The probability of a pellet impacting in that range is 0.495. The ratio between these two probabilities is, funnily enough, the same ratio between the 109 pellets in the 20" circle and the 150 in the 30" circle.

Two different linear densities; one probability function.

Therefore, if you start with the 20" circle and multiply up to find the same linear density for a 30" circle, you will vastly over-estimate the number of pellets required. Likewise, if you were to start with a 40" circle and multiply down for a 30" circle, you would vastly under-estimate the number of pellets required. The only way you can work it accurately is to know the probability function, which is the same for any size circle where a single gun / cartridge / choke are concerned. The example above is illustrative, but it should show why the standards we're working to are really probability functions and not densities.

Edited November 21, 2017 by neutron619

[Ultrastu]

I love the technical side of shooting .

But this isn't my area of expertise  .

Very much appreicate the time and thought gone into the thread and you guys are to be applauded.  I doff  my cap .

[islandgun]

1 hour ago, Ultrastu said:

I love the technical side of shooting .

But this isn't my area of expertise  .

Very much appreicate the time and thought gone into the thread and you guys are to be applauded.  I doff  my cap .

My thoughts also (but better put)

[wymberley]

14 hours ago, neutron619 said:

Ok - let's try a quick and dirty example and then I'll leave it before the OP / mods try to assassinate me or shut down my account.

Scenario: you want 150 pellets in the 30" circle at any distance.

The linear density of that pattern, if you get it, will be 0.212 pellets per inch (150 in 706 square inches).

You look at your tables and find that that's equivalent to 109 pellets in a 20" circle, which is a linear pattern density of 0.346 pellets per inch (109 in 314 square inches).

Why? The reason for this change in linear density is the fact that the pattern is described by a probability function.

Take a look at this: http://onlinestatbook.com/2/calculators/normal_dist.html Use a mean of 0 and a standard deviation of 1 to keep things simple.

Let's say our 30" circle is "standard" and therefore equivalent to the range -1 to 1 on the probability scale. The probability of a pellet landing inside that range for the function illustrated is 0.6827. Now reduce the diameter of the circle by 33% to represent a 20" circle - equivalent to a range of -0.666 to 0.666 on that graph. The probability of a pellet impacting in that range is 0.495. The ratio between these two probabilities is, funnily enough, the same ratio between the 109 pellets in the 20" circle and the 150 in the 30" circle.

Two different linear densities; one probability function.

Therefore, if you start with the 20" circle and multiply up to find the same linear density for a 30" circle, you will vastly over-estimate the number of pellets required. Likewise, if you were to start with a 40" circle and multiply down for a 30" circle, you would vastly under-estimate the number of pellets required. The only way you can work it accurately is to know the probability function, which is the same for any size circle where a single gun / cartridge / choke are concerned. The example above is illustrative, but it should show why the standards we're working to are really probability functions and not densities.

My problem is is that my age I'm shedding brain cells by several million per day and i was never the brightest cherry to start with. I follow what you're saying - I think - but got somewhat confused by the 109 - 150 ratio. As far as I'm aware this will not occur in any practical conventional choke ratio. However, I'm always open to correction. In fact I'd welcome it as it would mean that I could cleanly and consistently shoot pigeon dead in excess of 40 yards using either, say, 30g of 6s or 24 of 7s through an Imp Cyl barrel.

Consequently and in view of the above, "keep it simple" has an element of selfishness about it. To my mind, this is simplicity itself:

As this is not my work, I must acknowledge the author: Ed Lowry, former Research Director at Winchester-Western Division of Olin Corp'. As we're live quarry shooters and not world class DTL or Trap shooters, I have combined the original inner 10" circle and the 10 to 20" ring percentages which I feel better suits our needs.

It's worth bearing in mind that as ever shotgun ballistic information is based on the average of any findings made during any research and that therefore some variations are to be expected for any individual gun/cartridge combination. Again, as ever, the pattern plate is the only certainty. It's just that we make a mockery of it all anyway as the biggest discrepency will be our own (human) inability to accurately judge distance out in the field.

Edited November 22, 2017 by wymberley

[neutron619]

4 hours ago, wymberley said:

I follow what you're saying - I think - but got somewhat confused by the 109 - 150 ratio. As far as I'm aware this will not occur in any practical conventional choke ratio.

Well part of the issue will certainly be that patterns are approximately, rather than exactly Normal in terms of pellet distribution, so you may never see that ratio in real life.

However, the 0.6827 value is a clue: you can view it as the performance of a choke giving approximately 68% in a given circle at a given range. Let's say that's the standard circle of 30". Have a look at the chart below. 68.27% of the values (i.e. the pellets) under that distribution fall within the range -15 to +15 (i.e. inside the 30" circle). The range doesn't actually matter.

If we then adjust the range of that distribution to -10 to +10 (e.g. a 20" circle), we can see that 49.5% of the values then fall within the highlighted range.

So, if the 68.27% performance gives you your 150 pellets in the circle, then the number of pellets which fall into the inner 20" circle will be (49.5% / 68.27% * 150) which equates to 109 pellets.

This is not dissimilar to the higher end ratios listed in your table above.

Edited November 22, 2017 by neutron619

[wymberley]

"so you may never see that ratio in real life"

The thing is is that I shoot in real life. Your curves relate to a 220 pellet shot load. The 109 pellet count is quite different from the 90 that my (Lowry) table even allowing for the sub 2% discrepency. Had that been 1 oz of No7, then the figures would have been 232 for the 30" and 168 for the 20 with 140 being my figure for the 20" which is a considerable differenc for the more commonly used pellet size for pigeon.

My bottom line on this is that I've been pattern testing for some 40 years. Because for whatever reason I went into print and it was read by someone who realised that I'd spotted something and also that I didn't didn't understand it. As it happened what I'd spotted was correct and my reader was kind enough to forward the information explaining why what I'd seen was valid. From that point - some 30 years or more ago - on, I have never yet had a pattern that strayed beyond the discepency level as above.

To save the strain on my brain which is now deperately in need of a rest, could I suggest that we suspend this and await the results of the project that you and Cookoff are about to undertake. I know that you are aware of this, but for anyone else that might be interested but doesn't know, the table above is not dependent upon range so will therefore apply to any distance that you finally decide to pattern at - all that matters is the overall percentage in the 30" circle.

[Sprucey]

Just stick to a 12bore. Much less faff. 

[TIGHTCHOKE]

13 minutes ago, Sprucey said:

Just stick to a 12bore. Much less faff. 

Not the adventurous type then, investigating the Small Bore cartridge and choke combinations is interesting work!

[Walker570]

I do pattern any new cartridges/loads in my 410 but I don't spend time counting the hits ... far more interesting things to do ...I just look at the result and put myself in the position of a pheasant/partridge/pigeon et al and say would I like to be in that position... job done.

 

[neutron619]

2 hours ago, wymberley said:

"so you may never see that ratio in real life"

...

I have never yet had a pattern that strayed beyond the discepency level as above.

So we're in agreement then? You're not seeing the mathematically ideal performance as I said you wouldn't, because shotgun pattern pellet distributions aren't exactly Normally-distributed.

Some points to keep it brief:

• Lowry's numbers are themselves averages. They appear to be a shorthand to the probabilities you'd get if you ran them through the normal distribution and then knocked a bit off, though I'm not disagreeing with the numbers themselves particularly - only saying that they will have been derived by precisely the method you appear to want to disprove. I've counted a few of the old pattern images I have stored on the computer and to be fair to you, they are good approximations of the results. They appear to break down at the extremes of performance and in the case of very small shot. I suspect the same is true of "doughnutted" patterns, though I don't have an image of one to hand to count and check.
• Lowry's numbers do not account for hot or cold pattern centres. Most patterns will appear to have cold centres compared to what the Normal distribution would predict, but that is because shotguns are an imperfect system. If all the shot stayed perfectly spherical and undamaged as it progressed down the bore, I suspect you'd see distributions closer to Normal. I'm interested to know whether you have an equivalent table for steel shot?

Ultimately, I don't think we're far apart. I would say however that the reason for mentioning all of this stuff in the first place was actually to address the apparent need for a 55g pigeon load, which I hope I've now answered.

[wymberley]

33 minutes ago, neutron619 said:

So we're in agreement then? You're not seeing the mathematically ideal performance as I said you wouldn't, because shotgun pattern pellet distributions aren't exactly Normally-distributed.

Some points to keep it brief:

• Lowry's numbers are themselves averages. They appear to be a shorthand to the probabilities you'd get if you ran them through the normal distribution and then knocked a bit off, though I'm not disagreeing with the numbers themselves particularly - only saying that they will have been derived by precisely the method you appear to want to disprove. I've counted a few of the old pattern images I have stored on the computer and to be fair to you, they are good approximations of the results. They appear to break down at the extremes of performance and in the case of very small shot. I suspect the same is true of "doughnutted" patterns, though I don't have an image of one to hand to count and check.
• Lowry's numbers do not account for hot or cold pattern centres. Most patterns will appear to have cold centres compared to what the Normal distribution would predict, but that is because shotguns are an imperfect system. If all the shot stayed perfectly spherical and undamaged as it progressed down the bore, I suspect you'd see distributions closer to Normal. I'm interested to know whether you have an equivalent table for steel shot?

Ultimately, I don't think we're far apart. I would say however that the reason for mentioning all of this stuff in the first place was actually to address the apparent need for a 55g pigeon load, which I hope I've now answered.

Let's just say I'm an old rigger chief and know it when I hear it.

[neutron619]

Just now, wymberley said:

Let's just say I'm an old rigger chief and know it when I hear it.

I'm sorry - I have no idea what that means - but we may as well leave it. ATB.

[Floating Chamber]

Shoot at their feet.

[TIGHTCHOKE]

9 minutes ago, Floating Chamber said:

Shoot at their feet.

Who, Rigger Chiefs?

[wymberley]

1 hour ago, TIGHTCHOKE said:

Who, Rigger Chiefs?

Makes sense, brain shot.