M19 mortar Mortar 81mm infantry technical data military medium m29 system gp inetres Patent us3782240
M29a1 81mm medium mortar 81mm mortar ammunition and fuzes Mm mortar
Mortar 81mm m880 ammunition military gp 81 srtr inetres infantryMortar mm m224 military handheld army fm m19 mode gun .
.
Patent US3782240 - Firing mechanism for mortars - Google Patents
81mm Mortar Ammunition And Fuzes
Mm Mortar - Improvised Weaponry - Bev Fitchett's Guns Magazine
M29A1 81mm Medium Mortar