Well I gave up the idea of the custom stock for now and bought the only bighorn stock they had at Canada shooting supply. 80 bucks, why not make life easy?
Turns out, it has very nice grain! I had to clearance the safety and gauge to get it to drop in the proper location since the NP03 block is smaller than the bighorn. Nothing you'd notice if I didn't point it out, especially after I touch up the bare wood.
I got some 35 yard shooting in, and it's landing JSBs on top of each other, but the drop is significant with only 750 fps.
She is LONG. 49" OAL. Not terribly loud report, but definitely has a loud ping and you know something is being shot. Not as bad as say an unshrouded discovery rifle or similar gun, but it sounds like I'm forging horse shoes lol.
It developed a leak at the valve/block seal, so I gotta get in there and fix that. I like the side fill port, will make tethering a breeze. Currently looking at maybe 6 mags/42 shots in its peak.
I might order another 357 barrel and cut it down and see what it does, because this thing is stupid long for my liking. If I can keep it in the 600-650 fps range with 8" less of barrel, I'd be happy. That'd put it around 40"- 41", which I could tolerate. Not too concerned with losing the power, it would still be in the 80 fpe range, and that's plenty for smacking pests and dumping the energy.
Don't mind the chunk of cardboard between the bottle and shroud, thats a temporary spacer to get rid of the droop it has. Guess the shroud/baffles at the end is pulling it down. I will make a spacer from black rubber, or have a band 3D printed.
I just added it all up, and im right about $525 for the entire build which includes the carbon fiber shroud kit. Much cheaper and more quiet than buying the bighorn, and I think I'm close to the same power as the stock 357 comes.