Polymer cartridges reduce ammunition weight by 25%.
Polymers are a promising alternative to conventional casing materials. They are very lightweight, disposable and malleable enough to achieve a perfect chamber seal. However, at least in the mid-1960s, only a select few laboratories are able to manufacture polymer casings of an acceptable quality at a steep cost. Furthermore, they cannot sustain great pressures. The only current advantage of this design is in its lightweight nature.