I have recently acquired George Gibbs single shot falling block rifle, right hand side marked Farquarson patent 41 , right hand marked George Gibbs Bristol, barrel marked Metfords patent M 18 with the Corn St address, there is no caliber marked anywhere, I was told it is .461 Gibbs #1 ,I would like to here from someone that knows and shoots these, as my goal is to let this gun hunt again.