Thanks,

That was my best ever 10 shot card.

Yes, the Gecos are not marked for head size.

I suspect the 4.49 / 4.50 designation is more to do with which machine or which die set was used to form the pellets.

I know it is not so critical with a 10m pistol, but even the same make and head size can make a huge difference to the groups at longer ranges with an air rifle. That is why it is often important to get pellets made from the same batch number. With JSB Exact the batch number is written on the same label as the head size.

I suspect with a pistol the only way to check for that TINY improvement between pellets at 10m would be to clamp the pistol and then test fire it at say 25 yards indoors? But I still think the shooter will always be the weakest part of the whole system accuracy.

HTH

Mark