Quote Originally Posted by Hsing-ee View Post
Yes 4mm would need to have a powerful spring and a tight-fitting pellet to make it work properly I think, and like you say, would make for an FAC level rifle. Might reduce efficiency with a weaker spring and make it harsh to shoot. Hmm. Maybe it works well with the leather piston washers as the piston velocity might be a bit slower?


I found that a leather washer coupled with the 4 mm transfer port had so much lost volume that the piston slammed into the end of the cylinder.

I fitted an O ring piston head and increased the stroke on my 35 to reduce the effect of the lost volume caused by the 4 mm transfer port.
This is how I ended up at 15 ftlbs.

When I destroked the gun down to 12 ftlbs I ended up with piston slam if I used anything other than proper Wasps.

I really must build my 35 up with my spare 2.8 mm transfer port cylinder sometime for comparison with the 4 mm cylinder.


All the best Mick