a power injector and a removable replacement faceplate therefor are provided along with a method of front loading syringes , particularly prefilled syringes , which have outwardly extending structure such as flanges which have been typically breech loaded or side loaded into injectors or operated in a hand held fashion . the holder or faceplate of or for the injector is provided with a set of jaws spaced around a syringe receiving opening into which a syringe is loaded , rearward end first , with the jaws in a retracted position , until the flange or other outwardly extending structure on the syringe is rearward of the syringe is beyond a locking position of the jaws . the jaws are then actuated , either by operating an actuator on the faceplate or injector or by twisting the syringe in the opening , so that the jaws move radially inward and close in iris - like fashion about the syringe . the jaws preferably engage a narrow ring along a juncture of the flange or other structure and the body of the syringe and make sufficient contact around the circumference of the syringe , with sufficiently small spaces between the contacting surfaces to avoid damaging deformation of the syringe during use and to effectively hold the syringe against forward forces exerted by the ram of the injector .