I initially started out with the angled PVC fitting for the barrel, but it made the whole thing pretty long...which is against what I was trying to do. So, I went with a reverse plunger setup, with a standard SNAP plunger head (twin endcap method, like in the SNAP-1 mk2). So, here's the result:
Yep, it's tiny. (If you haven't guessed, the M is for Mini, SNAP-4 because it's a revrse plunger. See, I really do have a system for these names.)
I went with a .5" endcap wrapped in e-tape for the end, rather than an endcap, for size. I may replace the bushing with a coupler, screwed in with the same method.
Pretty comfortable right now, in spite of the "alternatve" ergonomics. I'm using one of my dogbones for a barrel (borrowed from the Duo), and a cut down SNAP spring. It's really a SNAP, just smaller.
Range: It's pulling high 60s right now....although, either the barrel is too short or I got some crazy darts, or the design causes it to kick up. I was getting the range, but accuracy (predictability) is low. We'll see how that improves with some work.