Just opened this thread and I’ll put my 2 cents in. I went through my phase of “prepping pellets” weighing, sorting by head size, sizing, lubing etc. I even went so far as to change the flare on the skirt and “increase” head size!. I spent alot of precious time trying to get that consistency and precision for any advantage in 25m br. Bottom line… your barrel either shoots that specific pellet or not! Now what I did find is this example, you have different lots of the same pellet say JSB 13.4’s different lots will shoot differently in your barrel “different die’s, different presses, pressures, die wear etc. you get the picture!!!”
Find the lot your barrel likes (which you probably just stumble on to) then try “TRY” to buy as many as you can!.
If you’re looking for precision just remember these are pellets not bullets and you are going to have those random flyers, velocity spreads etc. that you can truly never eliminate.
If you’re shooting under about 900fps lubricants are not going to stop fouling only add more variables to your accuracy!
My 2 cents worth!