0128160059b January 27, 2016 at: 1500 × 1155 In: In Search of The Goldilocks Round: Intermediates From 1860-1943 ← Previous Next → Six representative early intermediate rounds. From left to right: .351 WSL, .30 M1 Carbine, 7.92×33 Kz.Ptr. 43, 7.62×39 M43, 7.62×45 M.51, .300 AAC Blackout.