Question: is 300 blackout the same as 7.62?
Answer: Though they are similar in overall size, the . 300 Blackout has a slightly longer overall length (2.26″ vs 2.2″), but the 7.62x39mm has a slightly longer case length (1.528″ vs 1.368″). The picture below compares a Norinco 7.62x39mm cartridge with a 122gr FMJ bullet to a Sellier & Bellot .