Yep, agreed on leather's ability to absorb and pass on moisture.

Maybe what we need are more pistol grips where the hand is in a much more relaxed state, with a palm shelf taking the weight of the hand and a grip arrangement (thumbhole or otherwise) that, through design, places no pressure on the web between thumb and index finger.

Some of the PCP FT rifles spring to mind, design wise, and rifles like the Pulsar and some of the "tactical" stocked Airguns with their pistol grip arrangements?

In fact, and I can't remember the model name off hand right now, there's that tactical stocked Crosman springer with pistol grip and a stock that you'd have to guess would allow for more straight line recoil.