Posted 17 August 2009 - 05:56 PM
Yeah, the basic gist was to have a very compact one handed homemade. This setup accomplishes many things.
If it wasn't obvious, the plunger tube and plunger are in the handle. It has a +bow style catch at the bottom, and uses a brake line trigger.
I worked out the potential spring energy (the overall energy that propels the dart stored in a spring [in a springer, of course]) to be ~60 foot-pounds (british version of joules). In comparison, a fully primed +bow is ~69 foot-pounds, but this plunger tube is only a grand total of 6 inches long.
Yes, the air volume is quite smaller. It is the same part as a +bow plunger tube, so it has the same diameter, but it is 3.75" stroke as compared to the +bow's 6" (often +1/4"). I (as well as others) have found, though, that the inane amount of plunger volume in a +bow isn't greatly utilized. That's why many people who rely on +bows go to 16"+ barrels if they're looking for extra range. The volume in the dcit is a good compromise.
This has no almost no dead space in comparison to a +bow, and relative to a rscb'd +bow, is insanely efficient. I'll get a close up picture of the connection uploaded later (with many other pictures), but basically, at the end of the plunger tube, the (slanted) tee starts, leaving almost no dead space. This effectively works as the brisc does, pushing the air into the back of the dart, instead of making it turn.
Overall, koree is reporting <=10-15 foot range decrease from one of the best rscb +bow's I've seen, yet the main body of this gun only measures about 2.5" wide by 10" high by 1" thick.