I had hoped just a good polish would sort this one out but from what's been said above it looks like I'll have to remove a couple of thou off the front of the piston. Gun didn't look like it had been opened so it seems it was put together with a tight piston cylinder fit. I always thought these old BSA's and Webley's were well made examples of good old British enineering so how would this one have passed inspection with such a tight piston ?