Hi there,

I had an FWB 80 which clunked on cocking, it is perfectly normal, same with early FWB Rifles. It was FWBs sliding sledge design of counteracting the recoil. Other match pistols and rifles of the period (such as Original) used an opposing piston design to counteract the recoil. I believe Air Arms used the sliding sledge mechanism on one of their sporting rifles.

Paul.