Q. When trying blackpowder handloads in the Model 1884 Springfield Trapdoor rifle, what is acceptable regarding pressure? A. Recommended maximum average pressure (MAP) for Trapdoors is considered ...

Allin, master armorer at Springfield Armory, perfected a forward-hinged breechblock that swung open like a trapdoor, earning its everlasting nickname. Commensurate with this was the development of the ...