When weighing my JSB's I keep everything between 8.35 and 8.5 and the rest are used for practice and plinking. I suppose I get around 200 per thousand that are used for plinking.
I have noticed however that there are the occasional pelelts that are quite a bit heavier or lighter, maybe 2 or 3 per tin. If by just weeding those out then I am not concerned with the pelelts but more me
the idiot squeezing ( or even yanking) the trigger.