Hi ,i own one of these bullpups,these are extremely rare and there were two models one i belive fitted with a bsa barrel and the other of which i own fitted with a venom hand lapped walther barrel,you can tell which by the outer diameter size 14.5 mm i think for the hand lapped walther barrel and smaller around 13 mm for the bsa barrel. Mine is superbly accurate and has a preference for air arms field and i have shot some 1/3" inch 5 shot groups at 50 yards wind free,do you have the removable cheekpiece on your one as mine has not? this is probably the rarest gun i will ever own,also i you give tony belas of daystate a call he will tell you all the history etc relating to this gun. That is where i got my info to this as when i saw it for sale it was only something that clicked in my grey matter that i remembered this gun and then tony told me there was a test done on it in one of the airgun mags in 88 and this is where i must have seen it back then as tony told me they were not comercially advertised,and they cost over £600 in 1988! anyway unique gun and i dont think i will ever part with mine.