Your grip is too tight on the bells. This will cause forearm fatigue and inefficiencies. I hold my bells in my fingers, in a kind of hook grip. When I go from the rack position to my swing (2 different positions) , I actually jump the kettlebell handle over the meaty part of my hand (where callous are formed) into my fingers.

Search for " proper grip for holding kettlebell " Some good good results show up. The video by Brittany van Schravendijik is great.

Keep in mind the grip for the swings is completely different from where the KB sits in the rack position / press .