B.S.A. Mercury 635 magnum .25

[Rog stickman]

Hi I'm new to this forum,I have been given an air rifle what I believe is a Mercury .25 magnum
I was wondering if it is worth getting it serviced as it is not very good at the moment
Many thanks Rog

[TonyL]

Welcome to the forum, Rog.

Definitely worth servicing the old girl as long as all the basics are there. They're quite well thought of and should provide years of loyal service and fun once suitably fettled.

[Dornfelderliebe]

When you get it running it will probably like Marks man .25 pellets. It will also probably require the usual suspects during the service along with a new spring. They are breech seal, piston seal and buffer washer.

What exactly is wrong with it at the moment?

[Josie & John]

Welcome Rog.

I had one of these during the 1990s and regret selling her.

They are quite desirable to BSA collectors and well worth restoring internally.

John

[Rog stickman]

When you get it running it will probably like Marks man .25 pellets. It will also probably require the usual suspects during the service along with a new spring. They are breech seal, piston seal and buffer washer.

What exactly is wrong with it at the moment?

Hi Thank you for your reply
I have put through a dozen or so pellets but it is miles out and agnum.25the scope is miles out as well I can see that the breach seal is worn so i would think the rest of the seals and main spring need sorting out as well.
overall it is in pretty good shape and there is no wobble sideways on the barrel, The other problem i have is i belong to a local shooting club but the maximum i can use there is .22 so i cant test it out properly and i dont know any gun shops around me that service air rifles

[Brad3]

Good gun. It's age if looked after fairly well (not even very well) will still be better than many guns a day old. I've got guns 70 years old better than some brand new ones. Much of springer gun build never really improved, they just used more efficient production techniques and cheaper materials. Just get it serviced, or follow a tuning guide for the BSA Mercury, its cousin and also a great gun.

[Rog stickman]

Many thanks for the support everyone ,does anyone know where i can get it serviced in Surrey?

[TonyL]

I can't think of anywhere off-hand as regards servicing locally. Possibly just an idea to have a ring round of shops within reasonable travelling distance. If you find one, ask on here first re reputation.

How far away is Rayleigh, Essex, from you? I think The Airgun Centre are still located there?

Would you fancy having a go at the service yourself? Myself and a fair few other people will be able to advise on how to do it (and there are many BSA fans on here). There might even be a tutorial over in the Collectable Airguns section - Idiots Guide to Classic Strips. And you should be able to find some video tutorials on the Internet.

The trickiest bit will be undoing / refitting the trigger / mainspring retaining block. But it's all do-able if you work steadily and diligently and they are quite easy to work on with no need for special tools. And you can be proud of yourself for a job well done.

As per above, a breech seal, piston seal, piston buffer and spring may be all the parts you need. And a small tub of moly grease. Unless you wanted to fit a tuning kit which will deliver more refinement.

[Waddy]

Hi Thank you for your reply
I have put through a dozen or so pellets but it is miles out and agnum.25the scope is miles out as well I can see that the breach seal is worn so i would think the rest of the seals and main spring need sorting out as well.
overall it is in pretty good shape and there is no wobble sideways on the barrel, The other problem i have is i belong to a local shooting club but the maximum i can use there is .22 so i cant test it out properly and i dont know any gun shops around me that service air rifles

My local range has a sign up saying no .25 rifles, however I asked the owner about it . When I explained that it was a sub 12 ft/lbs rifle I wanted to use & not FAC he was happy for me to use it there.

No harm in asking, a sub 12 .25 won't do any more damage than a .22


.

[Dornfelderliebe]

My local range has a sign up saying no .25 rifles, however I asked the owner about it . When I explained that it was a sub 12 ft/lbs rifle I wanted to use & not FAC he was happy for me to use it there.

No harm in asking, a sub 12 .25 won't do any more damage than a .22


.

Make it clear to them that it is sub 12 ft lbs then they should be ok. I recently rejuvenated a Meteor and the breech seal alone knocked 200 fps off it. Your Magnum will be be nice once done up.

Older Mercuries and Airsporters tend to seize up the trigger block to the cylinder, this can be remedied with patience and easing oil. A competent gunsmith will have no problem.
You have a fine rifle there it will reward you if you put some effort in.

[Josie & John]

Many thanks for the support everyone ,does anyone know where i can get it serviced in Surrey?

Try Fultons on Bisley camp. They have a resident gunsmith.

John

[look no hands]

Try not to shoot it too much until it's been serviced, the internals can lock up if the buffer washer has disintegrated, then it's great fun trying to get the piston out.

[Dornfelderliebe]

Try not to shoot it too much until it's been serviced, the internals can lock up if the buffer washer has disintegrated, then it's great fun trying to get the piston out.

My last auction buy was like that, described as firing at about 250 fps it mysteriously locked up by the time I got to it. I now use a long pin punch which will just fit through a Mercury transfer port and plenty of lubricant.

[look no hands]

My last auction buy was like that, described as firing at about 250 fps it mysteriously locked up by the time I got to it. I now use a long pin punch which will just fit through a Mercury transfer port and plenty of lubricant.

I had to do that with a Challenger once, I used one of those really long thin screwdrivers and tapped it down, so it's the first thing I do now if I get a new Merc or 'Sporter is to take it apart and check it.