Tuning and Spring Surgery

[SRV1]

Please may I ask.....

I have stripped and rebuilding a 0.22 BSA Superstar Carbine, being a bit harsh and boingy with its original spring I have completed the following:
Discarded the original spring guide and turned a delrin replacement along with top hat.
Using a Titan No.1 with 31 coils, I initially removed two coils, carefully lubricated, assembled and tested, running a bit hot.
Removed another coil, ran hotter!
Removed another coil (down to 27) still a bit hot, but, not consistent velocity. Maybe, could this be due to lubrication/grease pattern before settling? No detonation evident....
Before committing further surgery on the spring, how many pellets should I put through it to stabilise lubrication/grease pattern if that is the cause.

All be it, the harshness has gone, smooth cocking....

I appreciate any help, or advise, and apologise if I am late in response to reply in kind.

All the best to all....

[Hsing-ee]

A whole tin (500) is a good idea, this gives the piston washer time to self-size, unless you have sized it too small in which case nothing is going to help.

Lube should be a stripe of moly grease at the back of the piston and the merest smear on the piston seal, and use a small paintbrush to paint a smear on the spring (I get the kids paintbrushes from Tesco, a couple of quid for 6 or so).

Good luck!

[SRV1]

Many thanks Hsing-ee for your response...

The piston seal was new from Chambers, no re-sizing, the fit seemed fine neither slack or tight, no different from my past dabblings.

Moly was lightly applied with my finger tip to back of seal and slightly more to piston body and the spring lightly greased. I applied Moly-Gn to cylinder with a cotton swab and then wiped with another clean swab so that it was the lightest of coating.

OK I'll put through pellets as recommended....
All the best.

P.S. Out of interest, anyone use a Titan No.1 in a Superstar and how many coils gave a good result?

[TonyL]

If still a little "hot" you'll really have to reduce the spring a little more. If you set it at no more than about 11.4 that should do it, as the power output is likely to rise as that new seal beds in. This will also have the benefit of even easier cocking, nicer firing cycle and even less strain on all components - linkages etc.

[Jenny Dipple]

I never lube the seal or cylinder, I apply a thin 5mm smear of moly on the front piston bearing and 10mm on the rear bearing; thin smear on spring ends, slip washers and top hat; shot variation is 0-10 fps! Jenny

[SRV1]

Thank you TonyL and Jenny for your response....I'll push some pellets through during next week or so, see where it's at, and adjust as required.

By the way, after cutting spring coils and compressing spring end, should one quench the end in water, oil or leave to cool naturally?

All the best....