Well, all credit to those brilliant people at Chambers. I'd ordered the breech seal on Tuesday morning and it arrived yesterday. Excellent service; thank you, chaps. Not the first time, either.

So, when I got the chance later yesterday evening, I popped the new seal in. A quick shot into the Argos catalogue would give a very quick gauge as to whether the hoped-for performance was restored..

Nope.. The dent in the catalogue was the same depth as when tried on Tuesday. Don't even need to check on the chrono. Now, spring resistance would seem healthy enough when cocking. And I noticed some dark, almost dusty, speckles on the catalogue. Peering up the barrel there are also tell tale little dark specklly "blobs". I think it's fair to say that the piston seal has degraded and has broken up, resulting in the dismal performance.