REVIEW BY RON FORSYTH AUSTRALIAN SHOOTERS JOURNAL /NOVEMBER 1992
Regular readers will be aware that some months ago here at the SSAA
we had a good look at
some of the problems that may be associated with the proposed changeover
to non-toxic shot.
The best lead shot alternative that anyone in the world has so far
been able to come up with has
without any doubt been bismuth. A few months ago, shotgunning circles
around the world were
alive with rumours. Bismuth was said to be as good as lead, it was
said to have been tested by
numerous different parties around the globe, and it was said to be
undergoing heavy
development. None of this was of any value to us in Australia without
specific testing results,
and so, as was reported in the ASJ of June, quantities of bismuth shot
were imported for the job
of gaining some up to the minute information about the way it really
does perform, and not just
the way it was said to. As a matter of fact, the things that have already
been said and written
about the subject by some overseas authors have provoked a bit of surprise
here at the SSAA. In
shotgun testing, there is not necessarily a lot of rhyme or reason
around the world. Many people
who launch into cartridge tests, for instance, may often just be playing
it by ear, without much
reference to past patterning data or to field experience. I believe
you can count on the fingers of
one hand the authors and organisations around the world from whom testing
results are really
reliable. I conclude from this that perhaps it may not be a good idea
to believe wholeheartedly
everything you read from overseas about bismuth testing. Enough said.
Shortly after we had
become aware of the state of play regarding bismuth imternationally,
we had sourced and
imported prototype shot in size seven, and it was soon evident from
testing here that this
patterned and performed just like lead shot. From a ballistic point
of view, the only difficulty
with it was that the shot size limited the amount of testing that could
be done. Number seven is
hardly the universal gamegetter, but that was all that was available,
so we began there. The
bismuth story continues to develop. We have now successfully brought
in sizes four, five and
six, and a great deal of testing has been going on since the completion
of the June article. So far,
the news is all good. Bismuth here in our hands has so far been loaded
with Red Dot, Green
Dot, Unique, Winchester 473 and 540, and Vectan D20 and A I . It has
been used in shot weights
from one ounce (28 gram) to ounce and half (42 gram) in not only 12
gauge but 10 gauge as
well. It has also been assessed in forty and fifty yard patterns, and
then used successfully against
feral pigeons and a wide variety of waterfowl, from teal to geese.
The result of using such a
wide variety of propellants is that I can confidently say that any
manufacturer would have no
problem in finding loads that pattern well. These powders listed above
span the fastest burning
to what is getting along towards the slowest burning of the commonly
available offerings which
are used in making lead-shotted loads. Almost all manufacturers of
ammunition employ a spread
of powders this wide. If I can select from this range, and come up
with good loads, then you can
rest assured that they will have no problems at all - and, if you 're
a handloader, then in due
course I doubt if you're likely to have any problems, either. At the
time of writing, there are
experimental aspects to bismuth, mostly related to the method of getting
it to form into pellets. It
will not readily adapt to a spherical shape in the same way that lead
does, largely because of
problems with its surface tension. When molten lead is released in
droplet sizes it actively
wants to make spheres, and so it lends itself to manufacture of shot.
Bismuth is not quite so
malleable. It is brittle in its natural state and tends to want to
fracture when it is cold and to form
discs when it's molten and hardening. However, rather than meaning
that it can't be worked into
spherical form to make pellets, this means instead that the technology
which has been devoted to
lead over many decades is to some extent no longer appropriate. New
approaches have to be
worked out, and possibly new machines put into place to handle them;
staff have to become
accustomed to operating them under new guidelines, and while this is
going on all the processes
of manufacture have to roll along until problems are brought out into
the open so they can be
dealt with. Because bismuth is just beginning to find commercial markets
around the world, it is
going to be loaded first by ammunition factories where for their daily
bread the management
make and load lead shot. Bismuth will have to be slotted in to an existing
structure of
procedures which, in the case of Britain, where most of it is being
loaded at the moment, might
have been in place for a hundred years. Any changes to this are obviously
going to have to
evolve, and this will take some time and care. Before any problems
which may exist can be
addressed, they have to become obvious, and the only way for this to
happen is that manufacture
has to take place as though lead were involved, and bit by bit new
procedures will be
organised. One area of concern that is getting massive attention is
pellet sizing. The long drop
method of shotmaking is not appropriate, so only the short drop can
be used. This is where
pellets are formed by a machine which sends molten shot mixture only
a few centimetres into
liquid, where it rapidly cools to form spheres. Short drop machines
are now quite common
around the world, the long drop being more expensive to work with unless
there is already a
long drop shot tower in existence. Shot towers are now few and far
between, but this is to the
advantage of bismuth; it has meant that most worldwide lead shot technology
over these last
years has been directed towards perfecting short drop shot manufacture.
The problem currently
under the microscope is that the surface tension of bismuth being what
it is, the pellets form into
spheres that are quite acceptable for use as shot in the sizes ranging
from nine down to four,
including half sizes. (This fact could easily become important in time
to come, because of the
small weight difference between lead and bismuth. With a little more
experience, it should
become possible to say how much alteration to choice of shot size will
be required. It may be
that half sizes are important, as shooters choosing bismuth slide up
to a slightly bigger size to
maintain the killing power of pellets equivalent to the lead sizes
they've always preferred. The
English in particular can be very fussy this way, and half sizes have
traditionally been offered
there.) Unfortunately, when the manufacture of bismuth gets up to size
four, that's the end of the
line, and anything larger when manufactured as though i t were lead
shot doesn't come off the
short drop machine and form into pellet shape at all, but rather just
as a blob that is roughly
disc-shaped. To overcome this, technicians are working on ways of raising
the surface tension;
at the same time, they are being extremely careful about this, because
there is no point in
developing an additive to increase sphericity if it is toxic. This
would obviously defeat the
purpose of having a non-toxic shot, and so they are carefully guarding
against it. The first
difficulties, mainly associated with the brittleness of the substance,
were quite quickly and
simply overcome by the addition of tin to make a bismuth alloy. This
has proved to be quite
workable, and of course tin is a common substance widely used to come
in close contact with
foodstuffs, so it has no toxic properties. This brings us to the point
where the SSAA had to
decide very quickly whether or not to become serious about the development
of this shot. Of
other options to lead shot there have been about thirty-seven attempts
from around the world,
and all have been found lacking until now. But once it became obvious
that there is genuine
potential in bismuth, and this was shown by the tests on the number
seven, then it fell to the
SSAA to pursue it and find out exactly what it has to offer. The big
requirement was for the shot
sizes which relate directly to the Australian waterfowl hunter's requirements.
The first tests
indicated that the shot was just a little lighter than lead, and so,
because sizes four. five and six
are the Australia-wide preferred duck hunting choices, we procured
these. At this point, there
was not enough number three to equip us with, but four to six were
no problem and these are the
sizes we have gone on with. Patterning tests were set up and these
were based on the results
which came to light in testing the number seven. As we draw closer
to the increased use of
bismuth, there will be time for specific loading advice. But already
there are many general
things of interest that have come to light. First, 22.5 grains of Vectan
D20 was the starting point
for some duck loads, for use over decoys against mainly teal with the
odd black duck thrown in,
using the number six and the number five. When patterned, this load
gave slightly denser
percentages than the equivalent load of good quality lead shot, perhaps
two or three percent
tighter, which is not a lot; however, because of the slightly lighter
weight when measured
against lead, so it is that the pellet counts are slightly higher for
the same weight. This meant that
an ounce and a quarter bush was required in the reloader to get a bismuth
shot drop of an ounce
and an eighth. This in turn meant the patterns increased even further
in density, because it was
not only the pattern percentage that went up, but also the overall
number of pellets placed in the
load to begin with. Taking my usual quarter and three-quarter choke
test barrels, this D20 load
gave quarter and three-quarter patterns which equated almost exactly
with Winchester lead shot
in the same sizes. Winchester shot is of good quality on a world basis
and it runs at around the
two to three Percent antimony level for its hardness. This patterning
confirmed the results of
previous experiments with the bismuth seven, which came in pretty close
to Winchester seven
lead shot as well. Having got that far, the next job was to take a
powder which performs quite
differently from D20, and see how bismuth would work out with that.
I selected Winchester 473,
as an example of an American style propellant with a more rapidly rising
pressure curve. One of
my favourite loads has always been 25 grains of 473 with an ounce and
an eighth of shot. This is
most appropriate for guns with a fair degree of choke, as it tends
to open patterns - the opposite
effect to the D20 load. The Winchester reloading guide tells us that
this load runs at 1255 fps
and 9,500 LUP. This is enough to put soft shot under severe strain.
There was no need to worry.
Run through the three-quarter choke barrel in a test series, bismuth
once again came up smiling.
The question this time was whether it would hold up under the sharper
pressure curve, or
whether it would need to be nursed by mild propellants in the same
way softer lead shot does to
avoid too much pellet distortion and hence too much opening of patterns.
The accompanying
table of performance will help to tell the story. In general, as regular
readers will know, the
softer the shot, the more open the patterns; antimony hardens shot,
so the lower the antimony, the
more likely the patterns are to be open. Using number five shot, the
three-quarter choke barrel
barrel produced 69% patterns at forty yards with 2% antimony lead shot,
and and 62% with 1%
antimony shot. This divergence is roughly what I would expect with
these two different grades
of hardness in this size. Both these lead loads gave patterns of good
distribution on the five
point scale of poor, fair, normal, good and excellent. With these patterns
established, bismuth
was tested, and it performed up towards the reaches of the harder shot,
coming in at 66%, and
making the barrel shoot exactly to its threequarter choke specification.
The pattern distribution
was normal. This is once again very heartening, because those who read
the June test of the
number seven bismuth may recall that when tested with Red Dot powder
in a one ounce load
and compared with lead, the bismuth patterns had a distribution slightly
better than the lead
ones. A movement like this, up and down the pattern quality scale,
is exactly what handloaders
expect when they test their reloads. The fact that with a change of
propel- lant the bismuth did
just a little better and then just a little worse in pattern comparisons
with lead is welcome news,
because it indicates that it flows through shotgun bores in much the
same way that lead does.
And just as lead can be manipulated with commonly available components
to make cartridges
that will suit different guns, so it is that bismuth can. With any
change from lead in the future, all
the combined experience of reloaders who have used lead for their shotgunning
is therefore not
going to be lost. It seems to me that for practical reloading purposes
we've got a straightforward
lead substitute here. When used against teal, the sixes performed beautifully
in a semi-auto with
a system of choke tubes, out of both quarter (.010") and half (.016")
chokes. Teal folded up the
way they ought to at ranges all the way up to forty yards. The odd
bird taken at longer ranges, up
to forty-eight yards, in fact, showed signs of good penetration, with
the pellets lodging just as
they ought, full up against the skin on the side opposite to the entrance
wound. Recovered pellets
showed no signs of having broken up. The kills were clean, and the
sixes proved adequate.
Some fives were used, mainly for second barrel loads, and the results
again bore out the
appropriate killing power of pellets made of the new material. In shooting
over decoys, I would
sooner use a six in the first barrel and a five in the second than
any other combination, and the
slight weight loss in the bismuth did not bring about any noticeable
difference in the field from
what would be expected with six and five lead shot under the same conditions.
There was no
crippling, no special allowance had to be made in terms of range or
forward allowance, and the
usual chokes were employed to achieve results that were in line with
what could be expected in
the shooting of ducks with lead shot. Grass whistle duck, being the
next step up from teal in duck
size, were the next species attempted, and the outcome was just the
same: dead ducks, with no
drama. Full chokes used against passing birds on big open water swamps
in the Northern
Territory brought about full range kills which could not be distinguished
from those made with
lead. So there you have the story to date. There's one last thing,
though, and that's the kind of
guns used to complete the tests up to this point. One of the major
problems with the idea of
alternative shot substances has been the question of barrel damage.
Bismuth shot in these tests
has been fired through all sorts of guns, including single barrel magazine
repeaters, under and
overs and side by sides. It should also be noted that it has been used
in American, Italian,
German and English guns, some of them being lightweight game guns with
thin barrel walls.
Wadding, of course, has been the standard plastic kind which is used
for making lead-shotted
loads, mainly AAs but also Gualandis designed for the straightwalled
European case. None of
the guns have suffered the slightest damage in the form of barrel bulging
or scoring of the bores.
In a recent development in the acceptance of bismuth shot around the
world, news from Canada
indicates that a large area in Ontario, the Wye Marsh, will have gone
over to bismuth shot by the
time this article is printed. Non-toxio shot is not mandatory for use
in Canada. The Wye Marsh
conservation managers have joined forces with Ducks Unlimited Canada
and decided to buy
bismuth ammunition for distribution to hunters who use the marsh. The
bismuth loads will be
either given out or sold to shooters at a heavily subsidked price for
use on that site. All Patterns
at 40 yuds Load: 25 gr Winchester 473, AA wad, M case, W209 primer,
1-1/8 ~ 5-shot. Choka:
.025', thre~q~ter. ~ismu h: - 66~ (strike of 180.274) Lead, 2% antirTlony
- 699~ (strikeof 167/
242) Leed, 1% antirnony -62% (strikeof 160/ 258) ~ ~.