airsporter s mark one rebuild advice please

[greasemonkey]

hi all ,following my previous post on this airsporter i have had my interest raised enough to keep it and restore it. [before buying a webley mk3 to restore].. stripped it last night and found out what it needs mechanically.spring is an ox square section,piston head is a non standard replacement turned out of alloy,buffer washer fell to bits upon removal.plan of action is replace all the above [chambers have everything apart from the mainspring].i am not looking for a powerhouse,just a smooth pleasant shooting gun.i will polish all relevant surfaces including the spring ends and am going to turn up some delrin washers to seat under both ends of the spring ,make a piston liner and hope i am pleased with the result.can any of the very knowledgeable and helpful chaps that frequent this forum advise on any tuning tips i have not got covered.i have read the very helpful sticky on this subject but would appreciate any advice offered...gun produced 9fpe before stripping and had nasty recoil[for an airgun]..cheers greasemonkey

[LeeH]

Sounds good to me, but I'd replace all the seals including thinly smearing some good grease in the action of the rotating breech to seal. Shame Chambers haven't got the spring in stock .. give John Knibbs a bell (01675 481006) ... their website has been 'under construction' for about a year

http://www.airgunspares.com/

They might be able to help.

Gun should go near enough full power without getting too severe I think?? I'm sure someone will set me right on that one. I rebuilt my bro-in-law's Airsporter about 3 months back. They are definitely worth the effort .. I love the trigger set up - so simple but really usable.

Have fun

[greasemonkey]

thanks for that, i will replace the piston o ring,what is used to lubricate o rings on airguns?i would have thought auto transmission oil or air tool lubricant but that seems too easy ..cheers..greasemonkey

[edbear2]

Hiya.......there has been a guy advertising genuine (he says he got them years ago at the BSA disposal sale).....Airsporter springs at quite a fair price (£11.50 posted!).......on fleabay........have a butcher's;

140382841605

If genuine, this is a pretty good deal, plus as the guy says, they will fit many other guns if you clip a few coils and regrind the end.....I have no connection with the seller.....

[junglie]

most good gunshops stock"airsporter" bsa springs, all modern bsa's take the same spring! I would put a titan or tr robb spring in because i've found 3 different models with broken bsa ones in in the last year! If you fit a bsa one grind out the end coil inside with a conical stone to ensure good fit on the guide & no binding. Good guide to spring finishing in new airgun sport mag march issue,with pics.

[LeeH]

thanks for that, i will replace the piston o ring,what is used to lubricate o rings on airguns?i would have thought auto transmission oil or air tool lubricant but that seems too easy ..cheers..greasemonkey

I use a drop of Abbey SM50 oil ... doesn't diesel like other oils ... remember less is more with all the lubes for the internals.

I only know this stuff because I read and contribute to the forums like you are doing. There's a lot of wisdom on here .. lots of chaff too if you're not careful

[LeeH]

Hiya.......there has been a guy advertising genuine (he says he got them years ago at the BSA disposal sale).....Airsporter springs at quite a fair price (£11.50 posted!).......on fleabay........have a butcher's;

140382841605

If genuine, this is a pretty good deal, plus as the guy says, they will fit many other guns if you clip a few coils and regrind the end.....I have no connection with the seller.....

looks like a bloody good deal to me. No connection here either.

[greasemonkey]

thanks for all info so far lads , much appreciated,i read in my newly aquired hilliers book that the barrel is screwed into the breech/compression chamber.this would be handy for when i have it reblued..do they come apart easy?..cheers..greasemonkey

[maximus]

No need to split barrel and comp chamber for re-blue. had mine done at Manchester a/guns, great job and cheap. I was not aware barrels were screwed in but you could do more harm than good if you tried to separate.
my .177 does about 9ft lbs and is all polished with thrust washers and plastic piston sleeve. Nice to shoot and accurate though. It may improve on the power front with use. I put a HW 95 spring in mine because I had one and it fitted. Hope it goes well.

Max

[T 20]

piston head is a non standard replacement turned out of alloy
..cheers greasemonkey

Hi Greasemonkey

The piston head on the UK spec S was made of alloy as standard.
The export head was made of steel and there were other 1-1/8" piston heads in the BSA range made from plastic.

I always lube the O ring and its groove with one drop of SM50 or MS50 (same thing).

The BSA factory used Rocol Kilopoise grease on the loading tap in a futile attempt to seal it.

Hope this helps

All the best Mick

[greasemonkey]

hi all,thanks for your info chaps .edbear ,congrats on reaching celeb status.maximus,i will take your advice and leave the barrel/chamber be as long as it fits in my refinishers tank.one of my customers is a electroplaters and does hot caustic blacking and does it for me at mates rates..[i wonder what a nickel plated airsporter would look like?]only joking!..mick,i thought this piston head was home brewed because i got the gun in a deal with an old mate who had owned it from new and told me his son had had one made for it..from what you have told me,maybe its an original part,but its a bit mullered anyway so i will buy a steel one from chambers as they are only a tenner.would a steel one have any effect on performance/recoil as it is heavier?... if it had been very expensive i would have tried machining one up out of delrin and making a ptfe seal..cheers greasemonkey

[pennineway.fswo]

hi all,thanks for your info chaps .edbear ,congrats on reaching celeb status.maximus,i will take your advice and leave the barrel/chamber be as long as it fits in my refinishers tank.one of my customers is a electroplaters and does hot caustic blacking and does it for me at mates rates..[i wonder what a nickel plated airsporter would look like?]only joking!..mick,i thought this piston head was home brewed because i got the gun in a deal with an old mate who had owned it from new and told me his son had had one made for it..from what you have told me,maybe its an original part,but its a bit mullered anyway so i will buy a steel one from chambers as they are only a tenner.would a steel one have any effect on performance/recoil as it is heavier?... if it had been very expensive i would have tried machining one up out of delrin and making a ptfe seal..cheers greasemonkey

Usually adding a little extra weight to the piston increases power. I replaced the alloy head in my .22 S with a steel one from T Robb. Power stayed virtually the same but the gun felt harsher to shoot, so I brought it back to standard
I suspect that every gun is different and what works in one may not work in another, but my choice would be an alloy one, although a delrin one with ptfe seal may well give some improvement. If you do machine one and try it please let us know how it preforms

John

[Airsporter1st]

If this is a 0.22 calibre then some of the harshness may be down to pellet choice. Try RWS Superdomes once you've finished it.

Good luck.

[T 20]

Usually adding a little extra weight to the piston increases power. I replaced the alloy head in my .22 S with a steel one from T Robb. Power stayed virtually the same but the gun felt harsher to shoot, so I brought it back to standard
I suspect that every gun is different and what works in one may not work in another, but my choice would be an alloy one, although a delrin one with ptfe seal may well give some improvement. If you do machine one and try it please let us know how it preforms

John

Hi John

I machined a Brass piston head for my S and found the same as yourself regarding the gun becoming harsher to shoot.

I did think about machining up a PTFE head but the breach block end of the cylinder is not flat.
I cast a piece of Isopon P38 in the cylinder to find the breach end profile before I machined the Brass head.
The cylinder's breach end profile looks like it was formed by a reamer - hence the radiused front edge on the standard piston head.
Of course my S cylinder could just be poorly machined and so different to other S's.

When I get five minutes I may have a go at machining a double O ring piston head with oil (SM50) reservoire in between the rings as used by John Bowkett.
His conversion of the S was found to make 12ftlbs with 12 coils removed from the standard mainspring (sounds good to me).
All I'd have to do then would be to cure the leaking loading tap.


All the best Mick

[pennineway.fswo]

Hi John

I machined a Brass piston head for my S and found the same as yourself regarding the gun becoming harsher to shoot.

I did think about machining up a PTFE head but the breach block end of the cylinder is not flat.
I cast a piece of Isopon P38 in the cylinder to find the breach end profile before I machined the Brass head.
The cylinder's breach end profile looks like it was formed by a reamer - hence the radiused front edge on the standard piston head.
Of course my S cylinder could just be poorly machined and so different to other S's.

When I get five minutes I may have a go at machining a double O ring piston head with oil (SM50) reservoire in between the rings as used by John Bowkett.
His conversion of the S was found to make 12ftlbs with 12 coils removed from the standard mainspring (sounds good to me).
All I'd have to do then would be to cure the leaking loading tap.


All the best Mick

Hi Mick
I will have a look through my old mags of AGW that date back to 1977 (I think) to see if I can find out more about JB's mods.
He really knew how to get the best out of an air rifle.

With regard to the leaking taps, my early (Airsporter Mk1's and 2's) with tapered taps seem pretty air tight, but later Airsporters certainly lose power due to air leaks at the parallel tap

I do have a .177 Airsporter S that is the exception and the tap on that gun holds presure very well. It is also nearly 1 ft lb more powerful than my .22 S, that does leak at the tap, so although everything happens very quickly during the firing cycle, leaky taps do mean less power

If you find a solution please let me know
ATB
John