Well, it looks like despite the scope behaving, it's started to misbehave on another springer, or another springer has started to misbehave, so that's now been taken off to rule it out entirely.
Update is that we've pulled the 97 apart, cleaned it up, changed the lube to Rocol and will see if she holds. We had to shim after reassembly, we don't know if the small nick in the transfer seal is causing the 35 fps drop or the Rocol has, but in any event she's shimmed up back up to around where she was, another scope has gone on top, and we'll see if she holds this time.
There's still slack in the cocking lever now though.
BFTA/NSRA County Coach
CSFTA Chairman/BFTA Rep