bolt bounce the cause since no cartridge to tension the assembly when the hammer falls ?
always seems to need a bit more effort to close on a casing so this would be my guess.
Been dry firing for over 25 years if anything the .22s would maybe develop a burr since the fp hits the breech face had a Ruger MK I that had that problem ironed it right out with a tool designed to solve that problem. Never a problem with CF