The test model was the early version that had a 2,700p.s.i (186 bar)charge pressure and gave shots in .22, 40 - 50 shots in .177.
The early versions had a 'silver' breech block but the later ones had a black one. I'm sure the later ones charged to 3000 p.s.i.(206 bar)
no longer in production as far as im aware