Post some pics of the longarms. Ole Nerke was a firearms merchant and more than likely sourced his longarms from Suhl. The G.L. Rasch is proabably based on Kersten's lockup. A Jackenroll mount is found on the Swedish Mauser M/41 Snipers(6.5x55mm). Is it a sidemount or center? Pics would be most beneficial. Do you have specific questions?

Kind Regards,

Raimey
rse