Big Sky Racks Shooting Accessories. Specifications for Big Sky One Gun Vertical/Horizontal Gun Mount BSR1: Mfg Item Num: BSR1 Supplier SKU: 27801 Category: GUN RESTS/BIPODS/TRIPODS Description: Gun Rack The Big Sky One Gun Vertical/Horizontal Gun Mount BSR1 is a quality addition to the Big Sky Racks lineup. For more great deals on Gun Racks by Big Sky Racks please browse our Big Sky Racks Gun Racks page.