I think this is the issue in nutshell.
Once we have selection of shells we know are safe to use in our guns, we experiment with them and settle on those which suit our guns. We don't care much about the figures.
For what it is worth, fro UK game shooting I use mostly Gamebore Pure Gold, Hull High Pheasant and Eley VIP in my 12-bores (No.6) but don't really care what the cartridges are as long as they are 2 1/2" and 28g, 30g. The loads I mention are not 'punchy', they pattern well and to tell the truth, I buy a couple of thousand at the start of each season and never think about what the ammo is doing again.
The guns I use are generally damascus barrelled,1870s hammer guns weighing around 6 3/4 or 7 lbs.
For super high pheasants there are much more powerful loads - see the wider range of Hull shells on the website - it gives data on each of them. I guess no marketing exec is going to launch a low partridge or 'average pheasant' cartridge - too much male ego to deal with!
