Being absolutely SMITTEN with repurposing ten-meter pistols to ulterior applications and having read about the Tau MK 08 some time ago, I recently finagled a trade for one in like-new condition. Of course before it arrived I milked the Google button on the interweb machine for all the information on the MK 08 I could suck out of it. A forum post buried deep in the bowels of cyberspace shed some very interesting insight.
According to the post, the side-lever-loadingTau PCP has not only a hammer-spring (power) adjuster hiding under the grip, but a regulator adjustment in the front of the trigger-gaurd. Furthermore, though the Tau website is in whatever hieroglyfics are employed in Czechoslovakia, a foot-note in the specs for the MK 08 stated "16J". I took that to mean 16 Joules, which I also took to refer to muzzle energy. Further employing the Google button with the entry "Joules to foot-pounds conversion", Google said that means 11.8 foot-pounds!
One huge atraction (for me) to the Tau was the side-lever loading, which should allow much lower mounting of a scope than my AZ-modified Steyr FT pistol. My only complaint about the AZ wunderpistol is the neccessity of mounting a scope waaay up in the stratosphere; even though Alan's barrel-clamping scope mount permits as low scope mounting as the shortened-as-much-as-possible loading lever allows.
Though no stranger to nice air pistols, on receipt of the Tau MK 08 I was floored by the beauty of the thing.
Chronographing revealed the expected four foot-pounds, and maxing-out the hammer-spring adjustment brought that up to five FP.
Indeed there was what appeared could be a regulator adjustment, right where the obscure forum post had said. Unfortunately it requires a specific size pin-spanner, and none of mine fit. Nevertheless I managed to coerce the adjustment in about a quarter-revolution at a time, each adjustment revealing gains over the chronograph. Much angst and aggravation later I'd managed to rotate the adjustment almost a full revolution before reaching the limits of my rudimentary "pin spanner". At that point muzzle energy was over 7 FP.
After fashioning barrel-clamping mounts to get the 4-12X Bushnell Trophy scope VERY LOW (as I like it), unfortunately neither 7.9 or 8.4 grain JSB's grouped well. With nothing to lose (before cleaning the barrel), I then tried 10.3 JSB's. BINGO... half-inch groups at 40 yards!!!
Furthermore, and as would be expected with a(ny) PCP, heavies return more muzzle energy. To be exact, 8.5 foot-pounds at 611 FPS. Though not yet the 10 FP (or more) I'm looking for, a better pin-spanner may yet get us there. Regardless, so far...
I'M A-LIKIN' WHAT THIS-HERE TAU'S A-DOIN'!