Short stroking a piston gun.

[Novagun]

Stumbled across an advertisement from TinBum tunes relating to a short stroke kit.

It looked to be a very simple piston cap that would fit over the dovetail of a piston to extend the length by 15 or so mms and the piston seal would fit on the end. It was the sort of thing you could turn up on a lathe in a few minutes.

The only advantage I can see is that it pushes the seal 15 mms closer to the transfer port. The spring and preload remain the same. The compression stroke would be 15 mms shorter in travel and a bit of a second shorter in time because of the modification. Shorter lock time. The volume of air being shifted would be a bit less and maybe the slam at the end of the stroke would be a bit harder.

I got the CFX out to give it try but a few shots and the old gun was shooting so well that I lost enthusiasm.

Can anyone report whether or not  the result is worth the effort?
Does the piston end cap need changes to the spring, top hat, preload to make it work with improvement to the gun?

[Franklink]

Worth the effort.

I put one of Tinbums short stroke nose caps in my HW77. I don't remember the length but it was the shortest one he offers for 26mm Weirhauch.  Power went from 12fpe to 10.5fpe but I also removed a 1/8inch washer/spacer from in front of the spring, other than that, it was drop in. My assumption was that the power loss was from reduced compression chamber volume.

Lock time was much faster, easier to shoot. Follow thru wasnt as critical.

[Novagun]

Right. I will have to try it on my Hatsan.