Hi there.

I've dug out my old BSA Mercury .22" (Mk3 I believe, SN# ZC07313) to dispatch some rats and rabbits we have in our paddock near to our new house. I stripped it down to replace the seals but there's quite a few problems I need to deal with and would appreciate any advice you may have to give.

The rifle is fitted with with a *shudder* ox spring and it's been in for quite a few years now (at least the 18 years since I got it) and it's done quite a lot of damage to the piston where the push-rod on the cocking mechanism has slipped. The outer edge of the piston has a large and deep gouge along its bottom section; ideally I'd like to replace it in its entirety but both John Knibbs and TW Chambers don't have any stock and won't be getting any more in. This just leaves me with the option of gently welding in the gouge and re-finishing it.

How do you remove the alloy hat on the front of the piston? I see there's something akin to a gudgeon pin holding it in but I don't know if it's tapped, an interference fit or something else?

The barrel is pretty sloppy on its hinge and I don't know if there are shims to take up the slack. The exploded diagram on Chambers' site is quite poor in this area so I don't know if such a thing is available?

The push rod that connects the barrel to the piston is missing a spacer and will need a new split pin. Not sure if it has any other method of being held as the diagram is again a bit rough.

My question is: are detailed stripdown manuals available for this rifle? I see there used to be ones available but were taken down for copyright reasons. I'd be happy to pay for one so that's not a problem.

As I'm new here it'd be useful to know how often Mercurys turn up for sale. Spares, repair or even a donor rifle would obviously be great as it'd let me get my rifle back into service. Are they reasonably common or like hen's teeth to get hold of?

Really I'd like to know whether it's worth fixing or not? It does have sentimental value to me so I'd not get rid of it if it wasn't. If it's not reasonably fixable then would a Diana 23 .177" (my other rifle) be any use on rats and rabbits? I've got a Nikko Sterling 4 x 40 scope on the Mercury right now but it could easily be moved providing the Diana has the rails for it (not sure as it's not here right now). If that's no good and the Mercury is fubared then what would be decent .22" full-power rifle to go for? I'd rather go for second-hand than new as I can't afford a good rifle and I really hate cheap chinese metal.

Thanks for any help you can give!

All the best.