An autoinjector comprising a plunger for engaging with said bung, a collar located around the plunger, an insertion spring biasing the collar relative to the rear of the device, and a delivery spring biasing the plunger relative to the collar. The device further comprises a stop feature defining the limit of axial movement of the syringe body through the housing, and a collar release mechanism for releasing the collar from the rear of the device to commence insertion and a plunger release mechanism for releasing the plunger from the collar while substantially preventing rearward axial movement of the collar, following insertion, to commence delivery of the medicament. Following release of the plunger from the collar, the plunger is configured to move axially and rotationally relative to the collar, the direction of rotation being changed one or more times with axial movement of the plunger.一種自我注入器，包括與塞子嚙合的柱塞，圍繞柱塞的套管，相對於設備後部偏置套管的插入彈簧，以及相對於套管偏置柱塞的輸送彈簧。該設備進一步包括：止動特徵件，用於限定注射器主體穿過殼體的軸向移動限度，套管釋放機制，用於從設備後部釋放套管以開始插入，以及柱塞釋放機制，用於在插入之後，在充分防止套管向後軸向移動的同時從套管上釋放柱塞，以便開始遞送藥劑。在從套管上釋放了柱塞之後，所述柱塞被配置成相對於套管在軸向上旋轉移動，所述旋轉的方向隨著柱塞的軸向運動而發生一次或多次變化。
