Abstract: A blowback bolt for a firearm has a distal bolt face having an axially relieved lower lip closest to the ammunition magazine. The axial relieved lip strips the lead cartridge from the magazine by contacting the rim of the cartridge and scoops it into the counterbore seat on the distal bolt face while maintaining contact with the rim. Chamfered lateral guides at the angular extremities of an arcuate upper guidewall restrict lateral movement of the rim during the scooping.

Abstract: A biased pivoting spent ammunition cartridge case extractor and retainer mechanism for blowback bolt firearms. The mechanism includes a distal arcuate hook shaped and dimensioned to intimately engage and nest into part of the circumferential groove in front of the cartridge rim. The hook remains engaged during blowback extraction of the casing from the chamber, and prior to ejection of the case from the firearm. The hook is formed onto the distal end of a rocking member secured to the bolt by a medial pivot. A compression spring bears against the opposite, proximal end of the rocking member thereby biasing the hook inwardly toward the counterbore seat on the distal end of the bolt into which the base of the case rests during extraction. A direct gas impingement system overcomes the biasing force of the spring to cause the case to be ejected.

Abstract: A biased pivoting spent ammunition cartridge case extractor and retainer mechanism for blowback bolt firearms. The mechanism includes a distal arcuate hook shaped and dimensioned to intimately engage and nest into part of the circumferential groove in front of the cartridge rim. The hook remains engaged during blowback extraction of the casing from the chamber, and prior to ejection of the case from the firearm. The hook is formed onto the distal end of a rocking member secured to the bolt by a medial pivot. A compression spring bears against the opposite, proximal end of the rocking member thereby biasing the hook inwardly toward the counterbore seat on the distal end of the bolt into which the base of the case rests during extraction. A direct gas impingement system overcomes the biasing force of the spring to cause the case to be ejected.

Abstract: A blowback bolt for a firearm has a distal bolt face having an axially relieved lower lip closest to the ammunition magazine. The axial relieved lip strips the lead cartridge from the magazine by contacting the rim of the cartridge and scoops it into the counterbore seat on the distal bolt face while maintaining contact with the rim. Chamfered lateral guides at the angular extremities of an arcuate upper guidewall restrict lateral movement of the rim during the scooping.