Starting in the mid 1920s the Belding & Mull Company of Philipsburg, Pa., known for their reloading tools, started producing a line of scopes (Stroebel, 2000). Several of their designs made use of a proprietary Trussed Hunting (TH) mount. The exact year of production is unclear but by 1929 the B&M Marksman was appearing for sale in printed adds. The end of production is likewise unknown probably occuring sometime in the 1940s either directly before or after the United States entered into WWII.
The Marksman was a 3x scope, 13in long and weighed 24oz with its truss mount. The scope was advertised as being nearly waterproof in part due to having no internal adjustments. All adjustments were made using the turrets on the truss mount. A number of different reticle were made including fine, medium, or course flat-top post and standard crosshair patterns (Stroebel, 2000).
Stroebel, N. (2000). Old Rifle Scopes. Krause Publications.