Well, with the help of C88machining parts and
@Firewalker cutting and crowning an FX barrel for me, here we are.
The parts list : plenum and extension, gauge block, and a 385mm barrel kit using a cut down 500mm FX slug liner.
I still have the reg set at the stock setting of 1900.
I've been meaning to report on how it's doing. I've got some numbers for those interested in bolt on performance.
IIRC CPHP 14.3gr were going 745-765fps before any mods
Here are feet per second and foot pounds of energy numbers with just the gauge block installed.
CPHP 14.3gr @ 825fps 21.6FPE
H&N Slug HP 21gr .218 @ 675fps 21.3FPE
FX Hybrid 22gr @ 637fps 19.8FPE
And the numbers with all mods installed.
CPHP 14.3 gr @ 875fps 24.3FPE
H&N Slug HP 21gr .218 @ 730fps 24.8FPE
FX Hybrid 22gr @ 685fps 22.9FPE
NSA 17.5gr .217 @ 745fps 21.6FPE **
NSA 17.5gr .2175 @ 745fps 21.6FPE **
** I didn't have the NSA slugs for the first test.
So it looks like the speeds are close to where I want to be, if accuracy is as good as it seems, I'll leave it alone.
Speaking of accurate, I can tell you what wasn't. The H&N HP slugs and FX hyrbid slugs - I think both are too big as evidenced by the tiny bit of extra force needed to load them and the jump in speed of the NSA's not that much lighter but smaller .217 & .2175 slugs.
I need to drag out some paper targets and put down some groups and see what's really going on.
What I do know so far is both NSA slugs are consistently hitting my 1" spinner @ 30yds and the H&N slugs and FX Hybrid slugs are not.
I'm still getting around four mags before it falls off the reg.
Just got a 3D printer so a new moderator will be a priority. Mine are for a .25cal.
I'm digging it as it is right now. The length and weight are still very manageable. It seems accurate with CPHP and the NSA slugs. It's been flipping my spinners a bit harder than before too.
What i gained...doesn't look like much. The power numbers have gone up a few ft/lbs. Speed has gone up by around 50fps.
I haven't tuned it in any way. That's next.
Reg and spring changes and maybe it gets even better.
We'll see.
Either way the squirrels won't like it.