It's down to the batch. I moved away from Fields, to Exacts, then Mozzies, then found that Fields were the mutts, only to go back to Mozzies. They all take the same wind within a smidge, and if some tins need nothing doing to them and shoot great groups and others need fettling to atomic consistency before they will do something 1/2 decent in comparison.
The problem is that when you've stuck 5-10 through the same hole at 55, you expect every pellet to do it and every tin there after.
Buy a shed load and shoot happy. Pellets aren't going to get cheaper. Even if VAT drops one day, i'm sure there'll be nothing moving on a tin.
BFTA/NSRA County Coach
CSFTA Chairman/BFTA Rep