Air Arms Owners Club

Hi

Iv been toying with the idea of short stroking my mk3 Prosport.
She already has a Tinbum gide kit in her.

Would the 14mm piston extension,put too much strain on the cocking lever?
I gather Nick (Tinbum) does a 10mm extension,which im thinking would cause less stress on the linkage.Iv heard stories
of the compresssion tube bolts being ripped out,with a 14mm one.

Any body short stroked their Prosport that can post their findings regards either of the two extensions.
And whether they kept the standard spring??

Many thanks!

Try dropping a mail to Nick (Tinbum) he must have some experience of users / experiences with his extension. The standard spring should work OK as the more efficient HW seal (vs the AA standard item) will compensate positively.
Ps there is a springer / tuning specific section on here now for you to use

I have messaged Nick via his facebook page begining of the week,but had no reply.
Sorry didnt realise id posted in wrong section.Can admin move it to the right one please

Timmytree on here is the resident Psport guru, and if memory serves ( not a given I am afraid) he was potentially s-stroking his a wee while ago?
I cannot guide you further not currently owning / nor previously short stroking a Psport but , no question with a TX (same basic internals) that reducing piston weight and short stroking can make an exceptional springer, akin to shooting a PCP.

I have short-stroked a .177 PS. . 10mm piston nose with walther LGU seal.(15mm total shorter stroke) Weihrauch seal would be 13mm which may be a better compromise.

With the standard spring and 10mm extra pre-load it was about 9 ft/lb and cocking effort a bit too high.

With a custom spring (similar to Titan No.5, sorry I can't remember the exact length) it was 11 ft/lb , manageable extra cocking effort and a noticeably quicker shot cycle.

regrettably I sold the rifle to fund other toys but I liked how it turned out. The slightly awkward cocking lever doesn't lend itself to short-stroking but as long as the bolt is fixed firmly in the comp tube it should be absolutely fine.

A .22 PS would be naturally more efficient and possibly an even better candidate for short-stroking.

I did try short stroking my PS. I started with a very smooth, civilized rifle doing an easy 11ftlbs. With the nose extension fitted it didn't feel much different except the power dropped and cocking effort increased. I didn't think there was any improvement gained and I certainly didn't want to increase preload, why make cocking the thing even more difficult?
Personally I don't think there's any big gain in doing to much to the PS beyond well fitting guides and a decent lube and making sure all the linkages and pins are tight.