Cotter pin anti rotation mechanism for accommodating sub caliber ammunition utilized in an ar-15 type firearm

Abstract

An anti-rotation feature incorporated into an interface established between a cotter pin and a sub caliber action device installable within an upper receiver of an AR-15 type firearm. A generally elongated receiver plate exhibits a generally lengthwise extending notched interior established between extending sides. The notched interior seats a bolt in reciprocating fashion along said receiver plate. A chamfer feature is formed in a side of the bolt in intersecting fashion with a selected length extending channel of the bolt for seating within the notched interior, the chamfer feature seating a head of the cotter pin to prevent rotation during bolt travel. A rearward projecting support sleeve includes an open interior for receiving and seating an opposing guide rod associated with a further mounting location of the receiver plate and in order to maintain in assembled fashion the forward assist adaptor. A firing pin exhibits a notch feature configured at a location along its shaft and which, upon installation within an interior aperture of the bolt, is retained in position by the cotter pin. The firing pin is configured so as to exhibit a reduced diameter end projection upon which is supported a coil spring.

Dependencies are inferred from the claim text.