Standard Armament Inc is a family owned business and was created with Howard Hughes in 1945. Their ammunition chute and handling systems are incorporated into almost every US weapon system.
SAI produces chutes that handle up to 30mm ammo. In fact, their 5.56 and 7.62 chutes are used by a couple of manufacturers for their dismounted ammunition pack systems.
Ask then how much they cost per foot? go ahead..
A big reason backpack mounted feed chutes for machine guns are so over priced..