Described is a medicament delivery device comprising a housing (102), a safety sleeve (106) movable between an extended position and a retracted position relative to the housing (102), a guide sleeve (114) rotatably disposed in the housing (102), a plunger (110) slidably disposed in the safety sleeve (106), and a button (126) coupled to the housing (102). When the safety sleeve (106) is in the retracted position, translation of the button (126) relative to the housing (102) causes the guide sleeve (114) to rotate relative to the safety sleeve (106). Rotation of the guide sleeve (114) relative to the safety sleeve (106) allows the plunger (110) to translate a predetermined axial distance relative to the safety sleeve (106).
