Hot-digity-dog! Sorry for starting a new thread on this gang...
Okay, I finished and tested the SSP valve moments ago! Don't have a 1377 [pistol] yet, but do have a carbine that was constructed out of one a year ago (the one for my daughter for when she is older). It was a real task to get the pump stroke to work being that I did not want to cut up her little carbine and put new holes in it. The rifle has a 16" barrel too!
First, it was tested without plugging the hole in the tube - got 223fps rather consistantly. I tried it plugging the hole (very, very difficult indeed - need three arms almost!). It fired 537fps! Holy smokes! I'm certain some of the air was lost since it was, again, very, very difficult to plug the hole with my thumb. Had to wrap electrical tape several times and then press with my thumb, while hold the pump rod in with a wodden rod. Hell, holding in the pump rod was almost impossible. In fact, when I fired the unit (my wife had to do it) the piston went in about a half inch - meanng I was unable to fully close it by hand. Little dude is not quite either! Sounds more like a little firecracker!
This is just too bad..., well, cool!
I am sooo totally excited about this! In the photo is one U.S. dime for size comparison.
"Well, I thought it was a rabbit but it turned out to be Bear Grylls in a rabbit hide."