Haha, dito mate. Great to be amongst other airgun enthousiasts like yourself. That's what makes this forum so great. I wasn't sure how they attached the barrel to the receiver, so I experimented on my own FWB300S, and it worked for me. No guarantee that it will work on others, they might have changed the production process, that's what I ment to say. So if it doesn't work on yours, share the production date (or serial number). Mine starts with 22 and was built in March 1977, making it one of the earlier models.