A medicament delivery apparatus comprising: a chamber (1062; 1262) containing a medicament (1060; 1260), and having a medicament delivery outlet (1064; 1264); a delivery assembly (1082; 1282) including: a chassis (1086; 1286) that is fixed, relative to the outlet (1064; 1264), to the chamber; and a fluid-displacement member (1010; 1210) that is configured to move relative to the outlet (1064; 1264) to move the medicament (1060; 1260) through the outlet (1064; 1264); and an envelope (1500; 2100) that: sterilely surrounds the chassis (1086; 1286); and encloses no residue from chemical sterilization, wherein: the chamber (1062; 1262) has a first electron beam or X-ray beam attenuation capacity; the delivery assembly (1082; 1282) has a second electron beam or X-ray beam attenuation capacity; and, the first and second electron beam or X-ray beam attenuation capacities are different, the first electron beam or X-ray beam attenuation capacity being greater than the second electron or X-ray beam attenuation capacity by a multiple that is greater than 1. a chamber (1062; 1262) containing a medicament (1060; 1260), and having a medicament delivery outlet (1064; 1264); a delivery assembly (1082; 1282) including: a chassis (1086; 1286) that is fixed, relative to the outlet (1064; 1264), to the chamber; and a fluid-displacement member (1010; 1210) that is configured to move relative to the outlet (1064; 1264) to move the medicament (1060; 1260) through the outlet (1064; 1264); and a chassis (1086; 1286) that is fixed, relative to the outlet (1064; 1264), to the chamber; and a fluid-displacement member (1010; 1210) that is configured to move relative to the outlet (1064; 1264) to move the medicament (1060; 1260) through the outlet (1064; 1264); and an envelope (1500; 2100) that: sterilely surrounds the chassis (1086; 1286); and encloses no residue from chemical sterilization, wherein: the chamber (1062; 1262) has a first electron beam or X-ray beam attenuation capacity; the delivery assembly (1082; 1282) has a second electron beam or X-ray beam attenuation capacity; and, the first and second electron beam or X-ray beam attenuation capacities are different, the first electron beam or X-ray beam attenuation capacity being greater than the second electron or X-ray beam attenuation capacity by a multiple that is greater than 1. sterilely surrounds the chassis (1086; 1286); and encloses no residue from chemical sterilization, wherein: the chamber (1062; 1262) has a first electron beam or X-ray beam attenuation capacity; the delivery assembly (1082; 1282) has a second electron beam or X-ray beam attenuation capacity; and, the first and second electron beam or X-ray beam attenuation capacities are different, the first electron beam or X-ray beam attenuation capacity being greater than the second electron or X-ray beam attenuation capacity by a multiple that is greater than 1. the chamber (1062; 1262) has a first electron beam or X-ray beam attenuation capacity; the delivery assembly (1082; 1282) has a second electron beam or X-ray beam attenuation capacity; and, the first and second electron beam or X-ray beam attenuation capacities are different, the first electron beam or X-ray beam attenuation capacity being greater than the second electron or X-ray beam attenuation capacity by a multiple that is greater than 1.