Interesting about the 91/30. I knew the Soviets supplied the Republicans with materiel, didn't know they sent small arms.
They actually sent quite a bit from what I've read. Many of the small arms were obsolete like Gras and Vetterli rifles chambered in BP cartridges but many were 91/30's which were new manufacture at the time. Stalin supposedly only included 100rds of ammo with the Vetterli's sent to Spain which basically made them useless. He also sent some light tanks to Spain as well but didn't include any spare parts or instruction manuals.