BASC Pattern Test - We need........

[wymberley]

I can't get this to copy/paste, sorry.

 

On Page 2 of the Topic article and under the heading of, "Minimum Number of Pellets Needed", the last word in the first paragraph is "overall" and is in italics - obviously for emphasis.

 

Could anyone familiar with this work kindly tell me what this means?

 

I can't decide whether it's on average, always, or whatever.

 

EDIT: Sorry, Guys, on reflection I didn't word that very well. I mean in context to the article.

Edited July 29, 2016 by wymberley

[TONY R]

Sorry i will, gladly try and help you but i see no article , are you talking about Tom Rosters work attached what do you want to know, and tables by any chance.?

Or if not Roster If you could put on a link please.

 

Roster 2012 lethality.

http://www.gfp.sd.gov/hunting/docs/NontoxicShotLethality_TRoster.pdf

Edited July 29, 2016 by TONY R

[seeker]

Its on p6 of my copy but i guess it's the same article. I read it as 'bird should get a minimum of 6/7 pellets to ensure at least 1 or 2 in the vitals....'. From memory Roster wrote of the 'probabilities' in stats terms.

Reading a bit further this is a article by John Harradine from 2002 onon Cartridge patterning.

Edited July 29, 2016 by seeker

[Stonepark]

I suspect it is this one from 3013.

 

https://www.google.com/url?q=https://basc.org.uk/wp-content/plugins/download-monitor/download.php%3Fid%3D724&sa=U&ved=0ahUKEwivoMuN6ZjOAhVoD5oKHRvdCeQQFggFMAA&client=internal-uds-cse&usg=AFQjCNHBEhV1wkAHKVYnUpTW5UQWepWkLw

 

 

Page 1 of 7
INFORMATION SHEET
CARTRIDGE PATTERNING
WE NEED TO DO IT - AND BETTER!
It is rare in any discussion about shooting and guns that the word ‘pattern’ does not occur. Much store is put
in what it reveals about gun or cartridge performance and the Gun’s success or otherwise in the field. The
use of a ‘pattern plate’ has also long been established to reveal the ‘patterning’ characteristics of guns and
cartridges.
But what do these terms mean, what can be learnt from the practices behind them, and how reliable are their
results? Furthermore, can any of these things be done better?
The word ‘pattern’ is used generally, but rather loosely, to describe the distribution of pellets on a surface
(usually a vertical ‘plate’) at which the cartridge has been fired. More vaguely, it is used for their distribution
at some point downrange on their way to the target.
The most common uses of patterning and a pattern plate include:
• testing cartridge performance, checking the chokes and regulating barrels
• checking gun fit
• checking gun mount
Only the first is considered here as it is by far the most important one, both in terms of extent of its use and
its considerable importance for shooting successfully with minimal wounding or loss of our quarry. The use of
patterning for gun fitting and gun mounting purposes is also important but best done under the guidance of a
person experienced in these skills.
How should patterning be done?
How patterning is actually done will depend on what is wanted. Here we are assuming that patterning is
mainly to assess the suitability of a given cartridge/choke combination to kill a particular type of quarry, such
as a mallard or pheasant, rather than simply break clays. As it is so important to ensure that any bird (or
animal) we shoot at is killed as quickly and as humanely as possible, we need to consider some more basics
first.
At what range?
Patterning should be done at the maximum range at which the shooter can consistently hit the quarry
species. This is likely to be a lot closer than the traditional 40yd! If it is 20yd, 25yd or 30yd, so be it – we
should be honest to ourselves and fair on the quarry.
The cartridge patterned should contain pellets large enough to ensure that, at the shooter’s maximum
accuracy range, they will penetrate to the vital organs of the quarry species. The emphasis on the maximum
range each time is that most shots are taken closer than that, and so the pattern will be more than adequate
to ensure a kill, while still ensuring that the occasional longer shot will also kill. NB. There is also a certain
minimum range for any load, in that the closer the target the tighter the shot cloud (or pattern). This
demands greater accuracy, but, if successful, may well spoil (i.e. waste) the quarry.
Page 2 of 7
How many cartridges?
Ten cartridges should be fired at the simplest of pattern plates/paper. For each pattern, in turn, a 30in circle
should be centered (by eye) on the densest part of the pellet strikes and the number falling within the 30in
circle, or touched by the edge of the circle, counted. The 10 pellet counts should then be averaged.
The need for at least 10 cartridges was shown most clearly by the former University College London’s
Ballistic Research Laboratory. To illustrate the variation that can occur, batches of ten cartridges from the
same box were fired (through the same choke) and pattern percentages within each ten varied from as little
as 23% to nearly 70%! [see “New views on choke”, John Harradine, BASC, 2001].
One of the risks arising from this variation is that the first shot produces a pellet count or distribution which is
close to what is expected – it may then be tempting not to fire any more. It is highly likely, however, that the
second cartridge would produce a very different percentage, the third another different percentage, and so
on.
With such variability between cartridges the average of a series of at least 10 firings is the best indicator of
the performance of a given cartridge. Fewer than that can give very misleading results. Clearly, for more
consistent and predictable results in the field, a cartridge type that shows minimal variation from cartridge to
cartridge is worth identifying.
Requirements for lethality
The key requirements for a consistently high kill rate (which all shooters strive for) are:
a) Pellets of the right size - so that, whatever the size, and distance, of the target, each pellet has
enough energy to penetrate its protective feathers/fur, skin, muscle and other tissues and reach its
vital organs (mainly the brain, heart, lungs and spinal cord)
b) Enough of those pellets to strike the target - to ensure that one or more vital organs are damaged, as
that is what actually kills (see below)
c) Accurate shooting so that sufficient pellets hit the target each time the trigger is pulled.
Minimum number of pellets needed
What is needed is a minimum number of these pellets in the 30in circle again at each person’s maximum
range, averaged over 10 shots. That number, based on highly detailed studies by American ballistician Tom
Roster, is at least 90 for a mallard or 100 for a pheasant at any range up to about 40yd. (Note that there are
a minimum number of pellet strikes needed for each type of bird (see Table 1), but none currently available
for animal quarry species). Provided that minimum number is achieved and the pellets are generally well
distributed over the 30in circle, then nearly every quarry species which is well placed in the pattern, should
be killed. Statistically, the necessary one or two pellet strikes on the bird’s vital organs, which Roster has
shown are required to ensure a quick kill, will occur in 19 out of 20 shots, and that in order to ensure those
strikes, each bird must be struck, with some 6 or 7 pellets overall.
If the minimum average number of strikes in the 30in circle is not achieved, then there are three ways of
potentially improving the strike rate
• an increase in choke (but be aware that the effect of choke is unpredictable as there is so much variation
from cartridge to cartridge)
• a heavier cartridge (with more pellets)
• a more dense shot type (which, by reducing the pellet size slightly, would allow more pellets in the shot
cloud)
Page 3 of 7
Species Minimum 30”
pellet count *
Small Duck (Teal) 145
Medium Duck (Wigeon, shoveler, gadwall, goldeneye) 120
Large Duck (Mallard, pintail, pochard) 90
Small Geese (Egyptian) 80
Medium Geese (Pink/Grey) 65
Large Geese (Canada) 55
Small game birds (Woodcock) 160
Medium game birds (Red-legged and grey partridges) 140
Large game birds (Pheasant, red grouse) 100
Medium pest birds (Jackdaw, jay, magpie) 180
Large pest birds (Woodpigeon, crow, rook) 140
Table 1: Minimum 30” pellet count for bird species
*These are based on 30 years of detailed American shooting research
The key is starting with the right-sized pellets (of a given shot material) which are suitable for the intended
quarry, at the range you can consistently achieve, and then being sure the cartridge/choke used will deliver a
killing pattern. Then, by shooting straight (the most important requirement of all), success should be assured
and few birds or animals wounded or lost.
Number of pellets not pattern percentages
If pattern percentages are wanted then at least three cartridges from the same batch should be opened, the
pellets counted and the average total determined. Percentages are not helpful in this context, however, as
pattern percentages themselves do not kill – it is the number of pellets that counts.
Traditional patterning – how it’s done
Let’s go back to basics with the widely-used traditional approach and use of pattern plates.
Both are variable and depend on the purpose in mind. Typically, a pattern plate is made of steel, at least 3ft
square and fixed some 4ft above the ground. The surface is painted with a thin whitewash (made from
hydrated lime and water), or sometimes sloppy estuarine mud, and a cartridge is fired at it usually from 40yd
away. A 30-inch circle is then drawn around the observed centre of the pellet strikes using a measured disc
or large pair of compasses, the number of strikes within the circle is counted, and they are expressed as a
percentage of the number of pellets in the original cartridge. Sometimes the number of 5in diameter ‘holes’
in the 30in circle are counted as well (i.e. areas of the circle where no pellets have struck). The plate is repainted
and possibly the procedure is repeated for one or two more cartridges.
There are many variations on this approach that have developed over the years:
1. A 30in circle is drawn or fixed on the plate, a cartridge fired at it and the pellets within the circle are
counted to give the pattern percentages.
2. Large sheets of paper or cardboard are fixed to a frame and one or more cartridges fired and the pellet
holes counted in the paper. The benefit of this approach is that the paper can be removed from the
frame after each firing and counted later and in some comfort. Clearly there must be a safety zone
behind the paper for the pellets passing through.
Page 4 of 7
3. Pre-printed 30in paper/cardboard circles are fitted to a similar frame, cartridges are fired at them and the
pellet holes counted.
4. Pre-printed 30in circles with printed sub-divisions of various sorts, including segments and often a 21in
inner circle (which divides the 30in circle into equal-area portions) are used to reveal more detail of the
distribution of pellets.
Some people use a digital camera to speed up the tedious process of patterning cartridges, by
photographing each pattern immediately for later analysis at a convenient time. The 30in circle must be
drawn, of course, before the picture is taken. This method can be problematic if many pellet strikes are
missed through poor photographic conditions.
How traditional patterning results are typically used
The results from these patterning approaches are used in various ways:
1. To check that a given cartridge (with or without a certain degree of choke) gives a ‘satisfactory pattern’.
This is generally considered to be a more or less uniform distribution of pellets over the 30in circle, with
few ‘holes’. NB. The results will apply only to the specific gun/choke combination used – they cannot be
assumed to apply to any other gun or choke.
2. To check that a given choke gives a ‘true’ pattern, by comparing the pattern percentage recorded with
the expected percentage traditionally associated with that degree of choke (namely, 40% with cylinder,
60% with half choke, 70% with full choke). Conversely such patterning is also used to find out what a
particular choke actually is. For example, if it produces a 60% pattern (whatever its actual physical
constriction at the muzzle) then it is deemed to be half choke.
3. To achieve a preferred pattern percentage or distribution of pellets over the 30in circle from a given
barrel/choke combination (‘barrel regulation’).
Problems with traditional patterning
The main problem is that if the purpose of patterning is to evaluate cartridge performance, check a
choke, or get a particular type of pattern, the traditional way of doing it may well produce misleading
results and the wrong conclusions. This is because patterning is often done or interpreted
incorrectly.
There are many causes of such problems:
1. A small pattern plate or sheet of paper may not capture all the pellets in the central 30in of the pattern,
especially if the gun is not fitting the user well or it (or the user) is not shooting straight to the point of
aim. This results in misleading pellet counts and percentages as well as wrong distributions of pellets.
2. Even on a conventional pattern plate or sheet of paper it can be difficult to draw a 30in circle over the
densest part of the pattern especially if the pattern is very widespread, thereby missing some of the
pellet strikes.
3. If a fixed 30in circle is being used then, unless gun fit and shooting technique are good, the patterns
themselves may well not be centered on the centre of the 30in circle. Again the result is that pellets are
not counted that should be counted, and unreliable results are obtained.
4. Expressing the number of pellets inside the 30in circle as a percentage of the total in the cartridge
requires the number in the cartridge to be known. This can be obtained from manufacturers’ figures,
published tables, estimated from the weight of shot in the cartridge, and so on. All these methods vary
and may not be wholly reliable, as actual loadings of cartridges can vary considerably. Opening a
cartridge is the only way to know precisely how many pellets are in each, but the numbers within each
cartridge also vary, so a minimum of three should be opened and counted to get an average.
Page 5 of 7
5. Firing only one or two cartridges of a given type can be highly misleading because of the considerable
variation in patterning performance from cartridge to cartridge even from the same box. A minimum of
five is required but even this is not very reliable. The aim really should be to fire 10 cartridges each time.
Only then is it likely that a reliable indication of the typical number of pellets and their general distribution
(and even the number of ‘holes’) over the 30in circle for that cartridge will be obtained.
6. Patterns conducted at the traditional 40 yards may be different from those achieved at the 20-30yards
which is normally used in the field. Similarly they may not reliably indicate the pattern beyond 40yd.
This is because as the mass of pellets (shot cloud) travels downrange, the individual pellets, after initially
interacting with each other, are moving in various directions. Moreover, the shot cloud can expand at an
increasing rate (trumpeting). The result is that the pellet distribution at any one point downrange cannot
reliably be used to predict what it will be at any other point.
7. The number and distribution of the 5in ‘holes’ (or ‘patches’) can also be misleading. They are often
interpreted as holes in the pattern through which a bird might escape being shot. (NB Birds do not fly
through shot clouds – shot clouds pass through birds!). But, of course, the number and distribution of
pellets on a pattern plate or paper is only a two-dimensional representation of a constantly-changing,
three-dimensional collection of pellets travelling downrange. At 40yd a shot cloud can be more than 5ft
wide and over 20ft long. The pattern of pellets on the plate or paper represents the accumulation of all
the pellets in the cartridge on one final surface – it cannot reveal the numbers and distribution of pellets
at an earlier time when the shot cloud and target bird meet. At most, ‘holes’ may only show up major
faults in cartridge manufacture, or barrel, but even this is not certain.
8. The nominal choke of the gun being used may not match the actual degree of bore constriction
traditionally measured at the muzzle. Perhaps more importantly, the whole choke cone profile may
influence the actual pattern thrown more than the particular degree of choke constriction at the muzzle.
9. Cartridges of similar specification but from different manufacturers, especially if the shot material itself is
different, can produce very different results even through the same barrel/choke, as the UCL Ballistics
Research Laboratory showed so clearly a number of years ago.
Are sub-divided pattern plates helpful?
Sub-division of the 30in circle into inner circles or segments is an option but generally contributes little useful
additional information on pattern distribution and can be mis-leading. It tends to focus undue attention on
individual patterns, whereas what really counts is the average performance of the given cartridge/choke
combination over the whole area. At most, an inner 15in circle (which actually constitutes one quarter of the
area of the 30in circle but may look as though it is half the area) can usefully indicate excessively tight
patterns, where most of the pellets are in the centre of the 30in circle, with few in the outer ‘half.
Page 6 of 7
In summary…
The simplicity of this approach to patterning is one of its attractions. It works for any bore of gun, as long as
it produces the appropriate minimum pellet count in the 30in circle. It avoids the complication and difficult
interpretation of counting different segments of the 30in circle or counting 5in ‘holes’ in the patterns, and
avoids the distractions of pattern percentages.
What is required is the rigorous approach of five to 10 cartridges being patterned correctly for each type
(=size) of quarry, and, if necessary, at different ranges. Patterning the gun once and assuming that that will
suffice for all types of shooting thereafter is inadequate, especially with non-lead cartridges, each of which
may behave differently with a given gun/choke combination. A snipe cartridge needs large numbers of small
pellets to ensure the bird’s tiny vital organs will be struck. A goose will need far fewer but much larger
pellets, because its vital organs are much larger and more effectively protected. For both types (= size) of
bird there is still a minimum number of pellets needed in the 30in circle at each person’s individual maximum
range, to ensure the required strikes on their vital organs. This is essential both to ensure a clean kill and a
quick retrieval, rather than the quarry being wounded and lost.
Page 7 of 7
In conclusion
It should be clear that a pattern plate has considerable value, but only if used in the correct way for the
purpose in mind. A vital first step towards improving shooting effectiveness for most shooters, is to check
that their gun fits well and that they are shooting straight. If we cannot consistently hit our target in the first
place we have a problem. Lack of success in the field can be due simply to poor gun fit and gun mounting
technique. At this point a few minutes with a qualified coach or an experienced Shot, perhaps at a pattern
plate, can be invaluable.
Another solution to the accuracy problem is to practise on clays at regular intervals, (especially the
unpredictable helice-ZZ-type!), if necessary, with the guidance of a coach. It is not defensible to practise on
living targets if the result is birds (or animals) being hit with only one or two pellets which are not going to kill
them.
Once we are shooting well on the clays, and consistently hitting all the types of target likely to be
encountered in the field, then we should go to the second step. This is to use the pattern plate to make sure
that we are using the right cartridge/choke combination to ensure that each bird or animal that is hit is killed
and nothing less. It will not always work, of course, but that must be the objective and we should not be
satisfied with much less than that.
Finally, it is essential to do the patterning exercise correctly, to get the most out of it. This is both to increase
our success of (and satisfaction) in the field, and to reduce unnecessary wounding and wastage of hit birds
or animals. No golfer uses one club for all shots on the course; no fisherman uses one rod for all types of
fishing. So it should be in our shooting. The right gun and the correct cartridge and choke should be used
for our intended target, each combination suited to the type of quarry, and within the range that each of us
can consistently shoot accurately. This can only benefit our shooting, our quarry, and the sport itself.
John Harradine
June 2013
Note. Grateful thanks are due to many friends and colleagues who helped in the original preparation of this information paper,
including especially John Batley, Robert Douglas, Roger Giblin and Tom Wylie.
The British Association for Shooting and Conservation
Marford Mill, Rossett, Wrexham LL12 0HL
Tel: 01244 573016 Fax: 01244 573013
Research@basc.org.uk www.basc.org.uk
Rec sec\publications\Cartridge patterning
Last updated: 06 Jun 2014 Review due: 30 April 2015

[Stonepark]

I never could get it to add up, i.e. the minimum suggested in Rosters tables and actual bird area as measured and available to be struck.

 

To me it reads that pellets must have a dense enough pattern to hit vitals with 2-3 pellets but due to pattern variation, at least 6-7 pellets must strike the bird and to which I agree, my problem is that 90 pellets for Mallard is insufficient to do this as a mallard represents a target (on average) of 30 square inches.

 

For 6 strikes, that would require a minimum pattern of 141 pellets (707 square inches divided by 30 inches squared times 6), whereas Roster recommends only 90 as a minimum.

 

My preferences are as follows inside a 30 inch circle: -

 

Geese 70

Mallard/Pheasant 150

Partridge/Pigeons/Woodcock 180

Edited July 29, 2016 by Stonepark

[TONY R]

I never could get it to add up, i.e. the minimum suggested in Rosters tables and actual bird area as measured and available to be struck.

 

To me it reads that pellets must have a dense enough pattern to hit vitals with 2-3 pellets but due to pattern variation, at least 6-7 pellets must strike the bird and to which I agree, my problem is that 90 pellets for Mallard is insufficient to do this as a mallard represents a target (on average) of 30 inches squared.

 

For 6 strikes, that would require a minimum pattern of 141 pellets (707 square inches divided by 25 inches squared times 6), whereas Roster recommends only 90 as a minimum.

 

My preferences area as follows inside a 30 inch circle: -

 

Geese 70

Mallard/Pheasant 150

Partridge/Pigeons/Woodcock 180

I think Roster tried to compromise with malards his letality tables shot sizes range and loads would mean 90 pellets would be abot all he could realistcaly expect at those ranges or his pellets would not have enough energey speed if he went smaller and he would have to go up in size and as such payload too from his lists , so he made a compromise i am guessing.,

I agree with you your numbers they are far more practical.

Edited July 29, 2016 by TONY R

[wymberley]

I never could get it to add up, i.e. the minimum suggested in Rosters tables and actual bird area as measured and available to be struck.

 

To me it reads that pellets must have a dense enough pattern to hit vitals with 2-3 pellets but due to pattern variation, at least 6-7 pellets must strike the bird and to which I agree, my problem is that 90 pellets for Mallard is insufficient to do this as a mallard represents a target (on average) of 30 inches squared.

 

For 6 strikes, that would require a minimum pattern of 141 pellets (707 square inches divided by 30 inches squared times 6), whereas Roster recommends only 90 as a minimum.

 

My preferences are as follows inside a 30 inch circle: -

 

Geese 70

Mallard/Pheasant 150

Partridge/Pigeons/Woodcock 180

Many thanks for that. I was referring to the version on the BASC website. It looks as though the consensus is that the "overall" equates to 'on average'. This is what I thought but was not sure.

 

It's hardly surprising that you can't get it to add up - there's some serious flaws dotted throughout the piece. For example, if you transpose your highlighted bit on mallard to pigeon, then the pellet count necessary becomes (using the '6' average) 265.

[neutron619]

I never could get it to add up, i.e. the minimum suggested in Rosters tables and actual bird area as measured and available to be struck.

 

To me it reads that pellets must have a dense enough pattern to hit vitals with 2-3 pellets but due to pattern variation, at least 6-7 pellets must strike the bird and to which I agree, my problem is that 90 pellets for Mallard is insufficient to do this as a mallard represents a target (on average) of 30 square inches.

 

For 6 strikes, that would require a minimum pattern of 141 pellets (707 square inches divided by 30 inches squared times 6), whereas Roster recommends only 90 as a minimum.

 

My preferences are as follows inside a 30 inch circle: -

 

Geese 70

Mallard/Pheasant 150

Partridge/Pigeons/Woodcock 180

 

I'm guessing here, but I would think that the thing that you're forgetting but which Roster has taken account of is that the pellets in the pattern aren't evenly distributed, but approximately Normally distributed.

 

What this means is that the linear pattern density for any given circle drawn within the 30" standard circle will tend to increase from the value for the 30" circle as the inner circle gets smaller (assuming they're centered on the same point).

 

In short, the "minimum" pattern of 90 pellets in a 30" circle is probably sufficient because the center part of the pattern (with which you hope you hit the duck) actually has a linear density of - say - 200+ pellets per 30" circle, which is easily enough.

 

Conversely, if you place the outside fringe of the pattern on the duck, the minimum linear density of 90 pellets per 30" circle will probably be substantially lower than what is required in the area covered by the duck and the bird may not be hit at all.

 

It would be interesting to know whether Roster, in presenting his data, is assuming that the quarry is hit by the center of the pattern, as this would confirm / deny my assertion.

Edited August 9, 2016 by neutron619

[wymberley]

 

I'm guessing here, but I would think that the thing that you're forgetting but which Roster has taken account of is that the pellets in the pattern aren't evenly distributed, but approximately Normally distributed.

 

What this means is that the linear pattern density for any given circle drawn within the 30" standard circle will tend to increase from the value for the 30" circle as the inner circle gets smaller (assuming they're centered on the same point).

 

In short, the "minimum" pattern of 90 pellets in a 30" circle is probably sufficient because the center part of the pattern (with which you hope you hit the duck) actually has a linear density of - say - 200+ pellets per 30" circle, which is easily enough.

 

Conversely, if you place the outside fringe of the pattern on the duck, the minimum linear density of 90 pellets per 30" circle will probably be substantially lower than what is required in the area covered by the duck and the bird may not be hit at all.

 

It would be interesting to know whether Roster, in presenting his data, is assuming that the quarry is hit by the center of the pattern, as this would confirm / deny my assertion.

Good post.

 

Thing is though, everyone is correct. It's also worth noting perhaps that the figures from Roster in this particular instance agree with our own home grown ones. Rosper's figures relate to the overall vulnerable area of a mallard and, give or take, the 90 in the 30" is good. Using the inner 20" circle as a 'kill zone' then a linear spread would equate to some 125 pellets (this is based on a 200 pellet load). Stonepark is also correct as he has wisely used an average figure for the vulnerable area (all targets are not always 'plan view'). This 'non linear' distribution is well documented and the figures are predictable - although with all things shotgun they are based on average findings and there will inevitably be some variation.

 

Somewhat of a guess perhaps, but there's probably an element of truth in that many of the studies from the USA have derived from the need to more accurately access lead shot performance to compare that of non toxic shot with it and as such this has, in the main, related to wildfowl. Consequently, it should come as no surprise that Roster's figures for mallard are pretty much correct. However, when it comes to pigeon it all goes to pot. The vulnerable area of a pigeon is about half of that of a mallard so it's logical that twice the pellet count is necessary - some (Stonepark's) 180and not the 140 quoted. Even then, there's a case to be made that even this is on the low side.

[neutron619]

Somewhat of a guess perhaps, but there's probably an element of truth in that many of the studies from the USA have derived from the need to more accurately access lead shot performance to compare that of non toxic shot with it and as such this has, in the main, related to wildfowl. Consequently, it should come as no surprise that Roster's figures for mallard are pretty much correct. However, when it comes to pigeon it all goes to pot. The vulnerable area of a pigeon is about half of that of a mallard so it's logical that twice the pellet count is necessary - some (Stonepark's) 180and not the 140 quoted. Even then, there's a case to be made that even this is on the low side.

 

Now this is where my maths falls down, so don't take what I'm saying as having any authority here (but I will try to work it out with pen and paper later).

 

I'm wondering if, because of the way the Normal distribution works, whether increasing the linear pattern density at the edge of the 30" circle by 50% increases the linear pattern density in the 20" hot center by more than 50%?

 

I haven't quite got the calculations sussed yet - it could be that doubling it at the edge also doubles it at the center - but it wouldn't surprise me if (all figures indicating linear densities) if 90 pellets-per-30"-circle gave a density of 150 pellets-per-30"-circle in a 20" circle centered on the same spot, whereas 140 pellets-per-30"-circle gave a density of 400 pellets-per-30"-circle in a 20" circle centered on the same spot (or similar).

 

I'm also trying to think along the lines of the 30" circle being two-and-a-bit times larger than the 20" circle and how the relationship between those two diameters might affect the numbers, but again, without pen and paper to hand to write down the calculations and work it out, I'm only able to add that as a line of thought that might be worth exploring to explain the Roster figure for pigeon.

Edited August 10, 2016 by neutron619

[TIGHTCHOKE]

And all of this still being looked at in only two dimensions!

[wymberley]

Some figures which might help, but again emphasize that these are liable to variation in individual guns. Additionally, any pattern examined is only ever two dimensional so it's down to the individual whether or not this gives a better idea of what's what rather than having no idea whatsoever. The table from which this is extracted is by Ed Lowry who was the Research Director as Winchester for some 30 years employed specifically for ballistic research. Because my name is not Ling, I find that combining the inner 10" circle to that of the 10 to 20" ring suits me better. It reflects that while working with the normal shotgun choke densities it is impossible to increase the outer 20 to 30" density by 50%.

 

With a 40% pattern the inner 20" circle will have 20.3% and the outer 20 to 30" ring, the remaining 19.7. At 70%, similarly, the figures are 41.4 and 28.6%. Yep, it comes close to the 50% but doesn't quite make it. The interesting thing is that if you continue tightening the pattern the 20" density becomes 46 at 75% and 51 at 80% but there's little or no increase in the 20 to 30" ring. Within the normal pattern percentages whereas the outer ring increase is marginally under the 50% increase at best (70% pattern), an increase in the 20" circle of 100% can be expected. This is why the 30" circle is only used for checking pattern designation as rarely, if ever, the effective spread exceeds 25".

Edited August 10, 2016 by wymberley

[TONY R]

And all of this still being looked at in only two dimensions!

Ok but why any more.? I have heard this mentioned so many times i have to ask the question, if you could explain i realy would be greatfull.

[TIGHTCHOKE]

Ok but why any more.? I have heard this mentioned so many times i have to ask the question, if you could explain i realy would be greatfull.

 

 

A pattern of pellets thrown from a 12 bore shotgun barrel is round in section, may well be elongated like an airship due to more choke and the front pellets will arrive before the rearmost.

 

Consequently looking at a 2 dimensional board which effectively collects the pellets is not a very good way of checking the 3 dimensional pattern thrown by a particular barrel, choke and cartridge combination.

[wymberley]

Ok but why any more.? I have heard this mentioned so many times i have to ask the question, if you could explain i realy would be greatfull.

Unless I misunderstand the question, it's because whereas the ballisticians doing the work recognised the potential this was never realised as somehow we collectively - the GTA, the cartridge makers, the shooting associations and ourselves, et al, allowed the Ballistics Research Laboratory to close once the report relating to the development and evaluation of NTS which it was tasked to produce and which which gave rise to its existence was submitted to Defra.

[TONY R]

Unless I misunderstand the question, it's because whereas the ballisticians doing the work recognised the potential this was never realised as somehow we collectively - the GTA, the cartridge makers, the shooting associations and ourselves, et al, allowed the Ballistics Research Laboratory to close once the report relating to the development and evaluation of NTS which it was tasked to produce and which which gave rise to its existence was submitted to Defra.

I understand what your saying and appreciate your input, but in acctual fact Fulchoke answered the question perfectly, Re Shot string , i felt that was what was meant, but not sure so asked.

Shot strig exists and it can vary a little but its use in the field is negligable at best the difference to lead pellets on a passing bird etc again exist but its slight and very much a moot point . Dont completly ignore shot string but dont wory too much about it either, the pretty pattern and how that pattern is spread out re% in the 30 inch circle is the key feature we need be concerned with. I know we are not turkey hunting well not many of us, but turkey hunters take patterning very seriously look on a board like this you might see the odd pattern pic if your lucky never very well definecd never marked in inner tens or inner 6s and relative %s just a photo off a phone, go on any turkey board in the states and your swamped with pattern pics of every ga every shot type more often than not well defined and explained.

I think pattern photos are what we are short of on here. Be intresting to see some properly laid out pattern %s and the zones of the pattern broken down in detail.

Ill try and do a few post them up show you what i mean, or look on the turkey boards and see for yourselves.

We need more patterns on here..

[wymberley]

I understand what your saying and appreciate your input, but in acctual fact Fulchoke answered the question perfectly, Re Shot string , i felt that was what was meant, but not sure so asked.

Shot strig exists and it can vary a little but its use in the field is negligable at best the difference to lead pellets on a passing bird etc again exist but its slight and very much a moot point . Dont completly ignore shot string but dont wory too much about it either, the pretty pattern and how that pattern is spread out re% in the 30 inch circle is the key feature we need be concerned with. I know we are not turkey hunting well not many of us, but turkey hunters take patterning very seriously look on a board like this you might see the odd pattern pic if your lucky never very well definecd never marked in inner tens or inner 6s and relative %s just a photo off a phone, go on any turkey board in the states and your swamped with pattern pics of every ga every shot type more often than not well defined and explained.

I think pattern photos are what we are short of on here. Be intresting to see some properly laid out pattern %s and the zones of the pattern broken down in detail.

Ill try and do a few post them up show you what i mean, or look on the turkey boards and see for yourselves.

We need more patterns on here..

If we still had the BRL we'd have photo's - in 3D - coming out of our ears. But I don't think there's much call for them on here. Back in the day, on top of the normal shot count calculations they used to add 10% to the figure to cater for shot string.

[TONY R]

If we still had the BRL we'd have photo's - in 3D - coming out of our ears. But I don't think there's much call for them on here. Back in the day, on top of the normal shot count calculations they used to add 10% to the figure to cater for shot string.

Man i would be interested to see that, We do need more patterns though even if it just encourages new shooters or old shooters for that matter to acctualy pattern a gun at a pattern plate.

Im serious now i was shooting in scotland a few years ago and i mett a wildfowler i had not seen for ten years or more, hes dead now, but after flight me and my mate were walking off, shouted if he was coming, he replied no he was hanging back to pattern a load or tw after they all had gone. Pattern them over the water. Now he had been at it 40 years or more .

And believe me he is far from unique its about the only patterning many bother doing.