BSA Airsporter Mk1 service

[jirushi]

Hi, I'm servicing a BSA Airsporter Mk1 for a friend. It wouldn't fire anymore, this was due to a problem with the tap.
Disassembly was pretty straight forward, except for the trigger block: it needed heating and quite a few blows from a synthetic hammer.
I'd like to ask for some advice on the piston seal please.
It is quite hard. I'm not sure what the criteria are for replacing it or re-oiling it. I have neatsfoot oil. Another question is how to get the leather seal off...
Many thanks! Louis

[T 20]

On the MK1 Airsporter there's a nut inside the piston holding the piston rod inside the body, once you've removed the nut you can pull the rod and seal out of the body.

The nut is a barrel nut with two cutouts in it so you'll need to make a tool to remove it --- I cut a bit of thick wall tube to fit the nut.

I think Knibbs sell a leather replacement seal, if not they are the same 1.1" OD as a BSA standard seal.




All the best Mick

[Shed tuner]

that leather seal doesn't look at all bad; I'd just stick a few drops of neatsfoot on it, rub it in, and leave it alone.

[Geezer]

that leather seal doesn't look at all bad; I'd just stick a few drops of neatsfoot on it, rub it in, and leave it alone.

That was my reaction too. Worth a try, will probably work, and avoids more hassle than replacing it. And there’s just something nice about rejuvenating rather than replacing.

[jirushi]

Thank you for the advice gents. I will gently rub the seal with neatsfoot oil and then see how the gun performs.

I am also doing some research on springs. The spring that was in the gun is bent.

I'll go for a Titan spring no. 1 (OD 21.0- ID 14.5- coil thickness 3.2- no. of coils 31- length 280 (mm)).
I've found an seller who will receive the spring and then make a delrin spring guide and top hat. I think that will improve smoothness.

I might have to take a few coils off the spring.

If the Titan spring doesn't work out well, then I'll get this one:
http://www.airgunspares.com/store/pr...t-No.-16-0672/

[Shed tuner]

titan springs are generally too stiff (even with coils removed) - I'd get something softer...

[watchsapart]

I have a mk2 Airsporter in bits at the moment, left mine soaking in Neatsfoot for a couple of days, came up a treat!

[jirushi]

Thanks for the advice @ Shed tuner and whatchsapart, very useful!

I will leave the Titan springs. Have just been in touch with Protek Supplies, and they have Airsporter springs in stock. I've bought one of those.

Their Meteor spring is excellent, much better than the one I bought from Knibbs and Chambers (both too long and stiff, causing harshness), so I hope the Airsporter spring is just as nice.

They also advised me to simply dip the tip of the piston, with the seal on it, in neatsfoot oil and leave it for a day or so. Sounds like a plan.

[Shed tuner]

Thanks for the advice @ Shed tuner and whatchsapart, very useful!

I will leave the Titan springs. Have just been in touch with Protek Supplies, and they have Airsporter springs in stock. I've bought one of those.

Their Meteor spring is excellent, much better than the one I bought from Knibbs and Chambers (both too long and stiff, causing harshness), so I hope the Airsporter spring is just as nice.

They also advised me to simply dip the tip of the piston, with the seal on it, in neatsfoot oil and leave it for a day or so. Sounds like a plan.

good call - I like protek's meteor springs too

[jirushi]

I thought I would follow up on this thread.
The Airsporter is back together and it shoots lovely.
I decided to try an acetal spring guide and top hat. Had those made by Punctum airgun engineering (also on Fleabay).
Alan was very helpful and made the parts for me, based on measurements that I gave and an Airsporter spring from Protek that I had sent to him.
Alistair aka Hsing-ee on here gave me some good advice about experimenting with a bit of silicone grease and a bit of moly grease on the leather seal.
The gun is consistent, smooth and doesn't diesel.
I ended up using the old spring. The Protek one is good, but quite a bit longer. I am lazy and went for the easy way. I think 9,7 ft/lbs is fine. No vibrations, just a thud.
I really like this Airsporter. It belongs to a friend, but I might try to find one.
The two stage trigger is nice too. The sears are now polished, as are the inside of the cylinder/cocking slot/cocking shoe/slot in piston/piston outer contact points.
A few coats of CCL oil on the walnut stock and some light rust removal with 0000 wire wool and Ballistol (except where the etching is) helped to improve the looks.
Cheers

[Shed tuner]

good result. Agreed on the power output; I find airsporters generally get harsher much above 10 FP, so keeping it a smite lower makes sense and is ample for it's likely usage.

[jirushi]

good result. Agreed on the power output; I find airsporters generally get harsher much above 10 FP, so keeping it a smite lower makes sense and is ample for it's likely usage.

Thank you. I don't value power so much anymore. Maybe I'm getting older? I like my Meteor that produces 7 ft/lbs best. I hit what I aim for. That's a lot harder with my more powerful springers. Pcp's, that's a different story. Recently I borrowed a friend's 300 ft/lbs .40" Epox Badger from the States. That's real good fun.

Something else: does someone know why BSA used different pieces of wood on the Airsporter Mk1 stocks? The only reason I can think of is that less wood is wasted? With one piece, all the wood between the "arms" is lost?