High birds
Current British shooting magazines are replete with stories of ever higher pheasants being shown over the guns at shoots where deep valleys favour such antics and 60+ yard birds are now commonplace; in fact tales of 80 yard birds and further abound. Those estates that can comply do so gladly and charge a premium, for the higher the birds the better.
However, reports have recently emanated confirming that the wounding rates are climbing disproportionately to the kill rates. It is said that when average shooters are exposed to really high birds, the bag of shot birds goes down and runners (wounded birds) also tail off – they either kill or miss. But when the so-called experts arrive, the wounding rate spirals upwards to the point where the pickersup complain about their dogs being overworked. Also, shot charges of between 1½oz and 2oz (42-56g) sized from No.3s to No.1s are being used.
The physics of the projection of small spherical lead balls from smooth narrow tubes into the atmosphere are immutable. The birdshot charge exits the shotgun muzzle at the barrel diameter and, losing the plastic or fibre wad, forms an eggshaped cloud which from an un-choked barrel expands at about 25mm per metre of travel (or 1 inch/yard) regardless of the size of the barrel, and this continues outwards. At 36.58 metres (40yds), which is the sure and ethical outer range of a 12ga, the pattern diameter is about 1.40m (55”) and the classical 76.2cm (30”) patterning circle will contain only 40% of the pellets. Using a full choke, the pattern will be about 1.07m (40”) wide and 75% of the pellets will impact the 76.2cm circle. At 54.86m (60yds), the
An overseas trend of “high bird” shoots should be condemned here in South Africa.
cylinder barrel puts only 18% of its pellets into the 76.2cm circle – obviously the pattern has failed; compare the full choke barrel at 32%. Extra-full chokes could be used, but there is always the possibility of ‘blowing’ the pattern with too much choke and anyway most estates mandate the use of fibre wads, which have the effect of widening patterns by at least one degree of choke compared to the plastic wad.
But the assured killing shot pattern diameter is not 76.2cm at long ranges, but more like 61cm (24”), so these are “best” figures. Also the shot cloud at 36.58m (40yds) is 3.05 to 3.66m (10-12ft) long; 50% of the pellets are in the first metre and 75% in the first 1.5m, the rest forming the tail; at 54.86m (60yds) the tail is much longer at closer to 5m (16ft).
What is also immutable is that the heavier the shot charge the more propellant is required to project it at the same speed. Should faster speeds be used to increase striking energy then in both cases recoil increases markedly. This can be counterbalanced to some extent by using a heavier gun, which if shooting from a peg at driven birds, is not much of a handicap. Longer barrels are touted for gun steadiness and swing, 32-34” now being the preferred lengths for high birds – in fact trap guns are very similar. But for the ordinary bird shooter, a 9+lb gun is tiring to carry all day long and gun-bearers are in short supply, especially in the UK.
Switching to velocity and kinetic energy, further truths unfold. A sphere has low sectional density, proportionally a large frontal area, a poor ballistic coefficient and sad aerodynamics. Small pellets lack mass, thus momentum, and run out of steam relatively quickly. Larger pellets have much increased drag and lose velocity almost as rapidly. The shot size that best balances mass against drag is the British No.4 at 3.05mm in diameter and weighing 0.167g (0.006oz) each (there are 170/ ounce, 6/gram).
Birdshot loses 30% of its velocity in the first 20yds, 45% in 40yds and 55% in 60yds, where a 1 350fps load is down to just 709fps while a 1 500fps load is only 16fps faster. So increasing the velocity does not help much because the faster the load, the faster it sheds its velocity until, as above, the down-range effect is minimal. The corresponding losses of striking energy are 50% at 40yds and 80% at 60yds. Moreover with heavy shot-charges, unless slower-burning high-quality powders are used, a very much increased percentage of the pel- lets at the bottom of the shotcolumn are rapidly compressed and consequentially deformed; leading to even wider and longer patterns.
It is accepted that, for a sure kill on a ring-necked pheasant (or a guinea-fowl) at 40yds, you need at least 4 to 6 pellets each with at least 1ft/lb energy to hit the central mass (which is not that big). A 1¼oz (36g) load of No.4s has 212 pellets, thus at 54.86m (60yds) a full choke 76.2cm diameter circle pattern contains just 68 pellets. The patterning circle’s area is 707.14sq. ins, so if the shot is evenly distributed, this is one pellet per every 10.4sq.ins which is similar in area to the pheasant’s ‘boilerroom’. Increasing to 2oz of No.4 shot with 340/load, gives 109 »
The shotgun was never intended to be a longrange weapon, the ballistics alone prevent it from being an efficient and reliable hunting instrument at anything over a maximum of 50yds.
» pellets at 54.86m, just short of double the number, but at one pellet per 6.49sq.ins, it is still not enough. Obviously the 1¼oz No.3s with 175 pellets/load, No.2s with 150/load and No.1s with 125/load will have even sparser dispersions.
Using the tried-and-true No.6 shot, the 1¼oz (36g) load has 338 pellets; with a full choke at 60yds it will deliver 108 pellets, or one pellet per every 2.1sq.ins – 5 to 6 times more than the No.4s and with a striking energy of a trifle over 1 ft/lb per pellet.
Granted the shot dispersion is never even over a pattern and the centre is always denser. But no one has ever been able to give definitive figures for percentages contained by smaller diameter circles as these vary widely from gun to gun and cartridge to cartridge. It is still doubtful however, that beyond 50 yards enough pellets, with enough striking energy, will be present for a sure kill.
STRIKING ENERGY
If you believe, as I do, that a shotgun kills with a combination of patterns (i.e. multiple hits) and striking energy; then the argument for large shot falls far short of expectations. Insofar as striking energy is concerned, there has always been controversy as to how much is required for a clean kill. Eley’s figures for pheasant are 4 pellets each of 1 to 1.5ft/lbs, many argue that our guinea-fowl need more, though in my experience this is not so. Their data for ranges beyond 45 metres and 50 yards are not commonly available and stop at No.3s, so the move to No.1s and 2s in the UK is un- precedented. The sad fact is that these sizes of shot will lose velocity faster than No.4s and thus striking (or kinetic) energy likewise.
Another factor against higher birds is the lead required. At muzzle velocities of +/-1 350fps, the shot will take 0.3 second to the target at 80yds, in this time the bird can easily cover 15-25 feet. Which is an impressively substantial required lead in any man’s language and not easy either to allow for or estimate.
The shotgun was never intended to be a long-range weapon, the ballistics alone prevent it from being an efficient and reliable hunting instrument at anything over a maximum of 50yds. A creditable report from the UK stated that at a “high pheasant” shoot where “experts” were present, over 1 000 shots were fired for a bag of 70 birds – a 1 in 14 success rate. So pure luck can’t be discounted – the golden pellet strikes again! Thus this fad for freakishly high birds should be condemned by all ethical wing-shooters. Hopefully such birds cannot be presented here, though it must be said that all too many long shots are taken at our undoubtedly toughest birds – the Egyptian and spurwing geese. * My background research picked up a useful tip – how to measure the height of a bird as it is shot. You will need a stopwatch; time its fall to earth and as gravity exerts a force of 32 feet per second per second, if it takes 2 seconds then the distance covered is 32+64 = 96 feet or 32 yards. Three seconds would be 32+64+96 = 192 feet = 64 yards.