Quote Originally Posted by CapitalBee View Post
Lewis, unless I'm corrected on this thread, I think it seems to have been resolved around the mid-80's (I've had a synthetic sealed 1980 hw35 with breech leakage).
I would also believe this to be the case, but couldn't be 100% sure. I can't remember if Mick, T20, had linked the cure to a particular event, process at the factory or timeline?

I'd never heard of it until the fine gurus on here enlightened me; mainly T20 and Bigtoe. At that point I already had a few 35s. One of them, the aforementioned "£30 basketcase", was at that point running at a very, very sweet 7ft.lbs. As I only intended to use it on open sights at close range down the garden (I have plenty of other full power rifles), the gun shot so sweetly and was so accurate, I'd sort of resigned myself to it being like that. Following those years of enlightenment, back in 2019 it received the later piston (courtesy of Mick), so lighter and more stroke, a new HW seal and sealed the breech using JB Weld Perma-Lock. Result? A nice, sweet 11+ in .177. Now, I wish I'd actually completed this in steps rather than all in one go as I'm really not sure what contributed most - the slightly increased stroke, resealing the breech or that nicely fitting new seal (as the Knibbs one was very, very tight). Guessing the latter two. And many owners of older rifles also report full power production with no issues.