Airsporter S good and bad ?

[El Garro]

I've been messing about with piston head conversions to enable parachute seals to be fitted and have seen some surprisingly different power levels between the 2 S's and 1 mk 5 I had
Ignoring the mk 5 which was a different design that had leaky joints, the S I've been working on at the mo will not go above 10.5 I realise there isn't much swept volume in them to start with but as I've managed to get a few more mm stroke by fitting the adaptor (could go more but need to make sure the cocking link has clearance and more importantly that the under lever drops down enough to be able to get your fingers around it before it starts compressing the spring) but still no real improvements. The shooting cycle is a lot better as there's no metal to metal contact at the end of the cylinder, I use a double o ring buffer with locating channels machined into the head to keep them in place and the piston is lined. I've opened up the groove on the parachute seal to make it more flexible and 'parachutey' yet power is still low. The tap seal is good too. No leaks. I've tried a few different springs including everyone's favourite, the trusty ox which have given the best results. Maybe as it's short on the stroke, a punchy spring works best ? Who knows
One thing has crossed my mind. I've noticed a lot of variation in dimensios on the standard airsporter so the big question is.....
Are there good and bad S models
Any ideas on that gents ?

Edit, just thought to add, it's a .22 mk 3 S and it was thputting out 9 with the old spring and o ring head.
Tried various pellets too.

[flatrajectory]

All Airsporters after the mk.2 are utter carp, that is all there is to it.
I have worked on hundreds of the damn things over the last 40 years so I do know them well.

I would not give one houseroom.

Pete. ( in foxhole).

[El Garro]

I'm tempted to agree with flatrajectory. I'm not keen on the early ones either to be honest.
They are nice looking things though.

[edbear2]

I'm tempted to agree with flatrajectory. I'm not keen on the early ones either to be honest.
They are nice looking things though.

Read Pete's post again!

Buy a Mk1 and play with that, you will be much happier

ATB, ED

[fatttmannn]

At the risk of offending, I love my series 1 Airsporter S in .22, never been able to fault it, and yes allso have a smashing Airsporter mark 2 from 1965 allso in .22, allso a Mercurey S series 2 in .177 thats very good apart from the triguer. oh and a Stutzen in .22

[El Garro]

Nice one ed. I won't be buying any more though. Played with some mk 1 and 2's and the odd one right before the 3. Nice, but not my cup of tea.
I'd like the R B2 carbine in .177 but they're like chickens teeth. I'll stick to the vastly superior supersports and lightnings I think (he says running for cover in readiness for what is coming )

[El Garro]

I've got a mk 2 S in .177 here too fattman, that's really sweet, I borrowed the spring out of that to try in the one I'm working on but it made less power.
That's what is leading me to think there may be good and bad ones.

[Big Seth]

[QUOTE=fatttmannn;6546831]At the risk of offending, I love my series 1 Airsporter S in .22,

Mk1 1"S" is a fine air rifle but the scope dovetails should have been cut deeper

[junglie]

I've only worked on one & the fit of the piston to cylinder was so bad it could only make 8.5 ft/lbs.I tried better fitting o rings to no avail. the RB carbine I had made high 11's easily with just new breach o rings.

[fatttmannn]

[QUOTE=Big Seth;6547028]

At the risk of offending, I love my series 1 Airsporter S in .22,

Mk1 1"S" is a fine air rifle but the scope dovetails should have been cut deeper

agree, mines retrofitted with the proper bsa scope stoap I found in a 2nd hand shop for 0.50p makes a hell of a difference when the scope stays put

[fatttmannn]

In the new year my Airsprtsr Stutzen and the S are booked in for a tune up with WelshWilli, be intresting to see how much they vary in performance. Will has one of the rare Airsporter Carbines, I like it but He wont sell

[T 20]

I've been messing about with piston head conversions to enable parachute seals to be fitted and have seen some surprisingly different power levels between the 2 S's and 1 mk 5 I had
Ignoring the mk 5 which was a different design that had leaky joints, the S I've been working on at the mo will not go above 10.5 I realise there isn't much swept volume in them to start with but as I've managed to get a few more mm stroke by fitting the adaptor (could go more but need to make sure the cocking link has clearance and more importantly that the under lever drops down enough to be able to get your fingers around it before it starts compressing the spring) but still no real improvements. The shooting cycle is a lot better as there's no metal to metal contact at the end of the cylinder, I use a double o ring buffer with locating channels machined into the head to keep them in place and the piston is lined. I've opened up the groove on the parachute seal to make it more flexible and 'parachutey' yet power is still low. The tap seal is good too. No leaks. I've tried a few different springs including everyone's favourite, the trusty ox which have given the best results. Maybe as it's short on the stroke, a punchy spring works best ? Who knows
One thing has crossed my mind. I've noticed a lot of variation in dimensios on the standard airsporter so the big question is.....
Are there good and bad S models
Any ideas on that gents ?

Edit, just thought to add, it's a .22 mk 3 S and it was thputting out 9 with the old spring and o ring head.
Tried various pellets too.

On the S that I have the cylinder walls do not meet the cylinder end wall squarely, by that I mean there is a small radius between the two.

I cast a small blob of car body filler in the end of the cylinder of mine to get the profile of the radius.

So a lip seal's lip will hit the radius before the piston head meets the end of the cylinder, this could tighten the piston seal at the point where it's under the highest pressure.


As others have said the Achilles heal on Airsporters after the MK 2 is the loading tap --- I'm happy with how my S is running but I'd still like to find a way of sealing the tap properly.


All the best Mick

[kemik]

Just had my 'S' .177 re blued and serviced shoots and looks better than new.

Steve

[El Garro]

Hi Mick, was the face at the end of the cylinder concave ? That's something I've not checked yet.

I'm wondering if the thread section is damaging the seal. I've taken to screwing the piston in until the seal clears the threads to save rounding off the lip.
I'm pretty sure this is a limiting factor to how big a seal you can fit in as the cylinder internal diameter opens up past it , meaning you need to squeeze the seal through a smaller hole than the actual compression cylinder. I'd guess that if you looked at the big picture, airguns were still developing when these were built. The move from leather seals to O ring (I hate this type) to PTFE, then eventually to the parachute seals we see in nearly all production guns now. Maybe it's a waste of time trying to improve the performance of some older guns. Perhaps optimising them would be more rewarding regardless of the power produced ?
Personally, I want more though

[edbear2]

Of course you could always buy a Mercury MK3 or S and have the looks AND the performance, I have always found them to shoot better than the Airsporter and given the choice would always go for the break barrel version (not the earlier pin barrel pivot, must have the adj type as per MK3 or S).

ATB, Ed