Different printing technology.
Emission of infrared radiation (energy) due to firing rather than due to body heat.
Munitions (such as rifle grenades, hand grenades, LAW) may be hidden behind textiles most of the time, only exposed during use.
Camouflage (such as netting) must not obstruct interface or operation of rifle (no problem with arms, for example).
Firing signatures are more important than weapon/munition visuals themselves.