A medicament delivery device (MDD) 10 has a syringe 12, a housing 22, a needle shield 24, a biasing member 26 and one or more blocking members 28. The needle shield is biased axially forwardly by the biasing member so as to selectively cover a needle of the syringe. However, the biasing member is prevented from biasing the needle shield axially forwardly until a radial movement of the blocking members has occurred, which is precipitated by a forward axial movement of the syringe. Consequently, the forward movement of the syringe releases the needle shield to automatically make safe the device. The MDD may further comprise a power source 44, which is can be actuated to move the syringe axially forward. The power source may comprises a compression spring. The power source may comprise a volume of a liquefied gas propellant, possibly a hydrofluoroalkane (HFA) or possibly a hydrofluoroolefin (HFO). The MDD may also comprise a means of priming the device.
