[The KG9 Kid]

"... The AK-47 is chambered for a 7.62mm x 54mm round..."

7.62x39, actually.

Or hey: 7.62x54 by New Jersey Supreme Court-interpreted election laws.

[infowarrior]

The original was chambered in 54mm, so that the rifle could accept both Warsaw Pact and the NATO 7.62x51mm rounds. The 7.62x39mm round is a "civilian" version of the weapon and the round became popular here in the US. I have a rifle chambered in 7.62x39mm (Ruger Mini-30)...

the infowarrior