The present invention relates to a medicament injection device (100) arranged to receive a replaceable container subassembly (103) The medicament injection device (100) comprises a front housing (102) and a rear housing (101) releasably connectable to each other. A reloadable drive mechanism (108) is accommodated in the rear housing (101) for acting on the plunger (14) of a replaceable container subassembly (103) for expelling medicament. A needle hider front is slidably arranged within the front housing. A needle shield remover (109) is arranged to connect with a needle shield of the replaceable container subassembly, wherein the needle shield remover is arranged to be removably inserted into a proximal end of the front housing through the needle hider front. The needle shield remover is adapted to be used to interact with the reloadable drive mechanism accommodated in the rear housing such that a user can reload the drive mechanism.
