Sorry it's taken me so long, here are some pictures.
I've added the piston and spring from my other 25mm internals 77k in .177, Venom is .22.
https://www.flickr.com/photos/152642.../shares/64Z765
This forum is a pain to add pictures to.
Thanks.
It looks like the venom seal adds a couple of mm of stroke.
Rich.
WANTED: Next weeks winning lottery numbers :-)