That's some air gun ,Air gun & rifles of large bore are historically found .But I never saw a modern maker produce one of that bore .But the 22 sorts are impressive if hardly traditional . A friend in Indiana John Hakes made a Austrian ?Military rifle now I recall, but not seen others. No real reason why a skilled artisan couldnt make one (.We Muzzle loaders are a pretty creative lot .)
.One word though of caution a late friend acquired an air Rifle by Stoudenmeyer a fine & noted maker. But he hydrolicked it using oil. He was demonstrating it at a clay shoot whenapon it diesiled and blew off his right hand ,sent part of the reservouir through his chest and left him with the two smallest fingers of his left hand .
But It didn't put him off ,I made him a left hand flintlock 12 bore and he was such a proficient he shot twice at the Internationals for the UK at Bisley , then the first US Matches held at Quantico Marine base. In 1981 from memory. I went over just to watch and there met Don Getz, Willis Boitnot and Hershal House Who I recall gave me a cloth patch 'Corps of Kentucky riflemen 'Among other noteable's I was later to better know .( I did' Do' 16 NMLRA' Easterns' other regional R vous 'and a raft of Fairs, Feasts, and Re enactments ) And married at Fort Ti F&I Grand encampment 1999. Did manage ' Death of Lord Howe' , a Culloden, Fort 4 Johnstons Hall , & one last Eastern .But along came children and that stopped my gallup !. What a waffle ! Regards Rudyard