When I found 42gram No.5 shot cases in a pigeon hide on a Norfolk pea field , my shoulder winced at the thought of firing such heavy loads at anything, let alone pigeons.
However, it made me consider what the most serviceable loads for pigeon shooting actually are. Leaving aside the controversial lead ban issue, lead has been proven to be the most efficient shot for killing game.
Over the years I have tried everything from 24 gram No.7 shot to 32gram 4s. I used to load my own cartridges years ago and tested all sizes of shot down to No.9. I am not a techno-ballistics buff, just a down-to-earth observer of what actually seems to kill best at the ranges I shoot.
"Lots of smaller pellets make a dense pattern while a large shot gives a greater thump"
The answer is not actually complicated and is a simple compromise between the number of shot in the pattern and the size of the pellet. Lots of smaller pellets make a dense pattern while a large shot gives a greater thump.
So it is the balance within any given weight of shot to achieve the most effective result.
A woodpigeon is not a big bird, and if you were to pluck one ,hang it up and look at it 40 yards away it would look rather small. Modern cartridges are effective out to 50 yards compared to with those us older chaps used in the 1960s. But, and it is a big but, the pattern must be dense enough to produce an adequate number of pellets to provide a clean kill. For this reason, given that my gun is bored half choke in both barrels, I have converted to a standard clay load of 28gram 7,1/2 shot.
Having always used 30 gram 6s, I was offered some 28gram 7,1/2 shot from the local game dealer. I was suspicious at first, but the proof that this load is effective came later in the field. The greater pattern density of shot more than compensated for the smaller pellet size. Cartridges have increased so much in price in recent years (due to the price of lead and components) that pigeon shooters are always on the look out for the best value.
No manufacturer can market a poor cartridge as competition clay shooting has ensured quality and consistency of performance. As the largest market is for clay shooting the volume of production enables competitive pricing. Therefore it makes sense for the pigeon shot to find a clay load that suits him, his gun and his pocket.
There is further logic for this as a clay pigeon and the body of a woodpigeon are targets of similar size. The fact is, that both need the same pattern density and pellet energy to break or kill the target.
An additional important factor is recoil and a pigeon shooter can fire a lot of shots on a good day. with a semi-auto, recoil is absorbed and heavy 32gram cartridges can be fired all day, but personally, I find that in normal circumstances, one does not need such heavy loads for decoyed pigeons. For normal shotguns 32gram cartridges would produce a headache or sore shoulder, and so light loads are sensible. For those using light game guns, a 24gram clay load is brilliant for most decoying days.
For the majority of us with normal guns, whether side-by-side or over-under, we are back to the compromise of preference narrowed down to 28gram or 30gram , with shot size No.6, No.7 or No.7,1/2. However whatever one uses, the unavoidable, fundamental truth is that it is not what you fire but where you fire it. That is what effectively and safely puts the birds in the bag.