The Erquiaga MR64 was a submachine gun designed by Peruvian firearms designer Juan Erquiaga Azicorbe in collaboration with Gordon B. Ingram, and manufactured by the Erquiaga Arms Company.
Erquiaga met Gordon Ingram when the latter visited Peru for a year on business terms. Ingram was very interested in submachine gun design and the two collaborated to develop the MR64. The MR64 was a hastily-designed submachine gun that was very quick, cheap and easy to manufacture. Thousands of MR64s were manufactured in Erquiaga's factory in California, and the purpose of their manufacture was to arm Cuban anti-government guerrillas. The FBI caught wind of Erquiaga's activities and raided his factory; US-manufactured weapons in the hands of Cuban rebels would have only worsened already poor US-Cuban relations. Erquiaga fled the US to avoid arrest.