sword
鏌 centers on a sword, specifically a type of blade or weapon made of metal.
鏌 combines 金 (metal) with 莫, which likely contributes the sound. The character is used for a type of sword, reflecting the metal radical.
The left side is metal 金, and the right side 莫 looks like a large blade with a guard. Picture a metal sword with a distinctive crossguard shape.
For バク, imagine a sword so heavy it makes a loud 'back' sound when it hits armor: back -> バク, and the metal blade clangs.