Harris Engineering 6A Adapter Rail American. OpticsPlanet Inc is an Authorized US Distributor for Harris Engineering Bipods. Adapter Stud #6A for American Rails. For American Size Rails 5/16 across rail slot Slides into 5/16 rails and locks into place with a set screw Specifications for Harris Engineering Adapter Rail American 6A: Manufacturer: Harris Engineering Fabric/Material: Metal Package Contents: Harris Engineering 6A Adapter Rail American We offer the complete line of Harris Engineering Bipods. For our complete selection of products by Harris Engineering on sale please visit our Harris Engineering page. For more Bipod Accesories please visit our Bipod Accesories store section. Harris Engineering 6A Adapter Rail American