the same components i used for .308 gave me nearly 450 fpe in .457 with a 405 grain slug.
this valve came to me in a dream...i was initially tired of emptying a bottle to change return spring rates, and after i went spring less in the old fascion desing it was clear that the spring and retainer really disturb the flow quite a bit.
i often lie awake long after going to bed (side effect of being a homegoing house slut lol) anyhow after 2 hours futurama, and family guy on adultswim(adult cartoons on cartoon network) which i like to watch, it nice and mind numbing, and i think real good with it on the tv....
anyhow....
this one solves alot of problems
1 air has to take just one turn(from sideways into portholes to straight forward) before it runs into the breech.
2 with a threaded tophat, you can change spring and adjust spring rate on the fly for what ever purpose you want....so this can go from being a .22 valve to a full blown .457 valve in just a switch of a tophat and return spring.
3 the long brass sleeve the stem moves in, doesnt need an oring as it it so long, this eliminates a problem i have had lately with orings stiffening up when its freezing outside, actually just cutting 1-2 oring grooves (without orings) is enough to eliminate any blowby (labyrinth seal i guess its called)
this stem pictured is one of my first, it will do more than 90 fpe in .22 setup, but it works in .308 as well pushing nearly 200 fpe.
i sort of went away from this valve a while back...while i think the idea is good....i had a very hard time drilling stems so deep in stainless steel, as my lathe has no cooling...this process would eat drills faster than i could buy them, and once a drill would have dulled and heat treatet the spot in the stem, i would have a hell of a time getting any drill to bite again...so for an IT dude...it became super frustrating...and we all know...anger leads to hate...hate leads to suffering...suffering leads to the dark side..and we dont wanna go there
with the right tools, and knowledge...i think this valve will be awsome..bet its not problem for a real machinist to cut a valve like this
improvements i have discovered since then
*to get he higher numbers...it needs to be enlarged abit, about .270"ID.
*portholes angled, takes the turn the air has to take from 90 degrees to about 40-50 degrees
*3 portholes, with bigger holes, flow more air than 4 portholes with smaller holes, yet it retains strenght
*delrin piece, needs to be cut as flas as possible with the center of it just ever so slightly undersunk 1-2 degree parabola, this will not deform, wedge, so it lasts alot longer, best of all force to open the valve is much more consistant this way.
*screw holding delrin can be sharpened, and extended into the porthole area, this will help in guiding the air, and gives a few fps extra
