http://www.patreon.com/ForgottenWeapons

Today we are taking a look at two unusual magazines from unusual firearms. These are a 60-round double-column mag from a Springfield 1964 SPIW bullpup and a 50-round box magazine from an AAI XM-19 serial flechette rifle.

For lots more information on Project SPIW, the best source is "SPIW: The Deadliest Weapon that Never Was".