This discipline covers the basic design features such as the trade-off between short recoil operation and gas operation of a semi-automatic firearm. Beyond that, this discipline includes all features of design and how that all adds up to a safely functioning firearm. It even includes such uncommonly understood, but vitally important features as a two piece firing pin. Or how a bolt notch above a two-stage trigger, serves double duty as a disconnector safety.
This issue of firearms design also includes the many safeties designed into a firearm; such as the positive safety, the trigger safety, the grip safety, the disconnector safety and many others. This category also includes proper machining techniques as called out in the manufacturing drawings, proper metallurgy, and all else in the design; as the engineer prepares and calls out the manufacturing drawings. LTC Alphin’s skills in firearms design was of particular use in the designer’s failure to ensure proper barrel steel in the Gellatly case. And the designer’s failure to have a firing pin retention device (ensuring that the firing pin cannot be blown out of the weapon) in the Mason case. These failures cost Mr. Gellatly his right hand and cost Mr. Mason his right eye. LTC Alphin was not only able to help get cash justice for these two men but also to force change which has avoided similar injuries for other people.