spear, lance, javelin
鎗 centers on a long thrusting weapon: a spear, lance, or javelin. The meanings are all variations of the same handheld pole weapon.
鎗 combines the metal radical 金 with 倉, which likely contributes the sound. The character originally referred to a metal-tipped spear or lance.
The left side 金 (metal) suggests a metal weapon, and the right side 倉 looks like a storehouse. Imagine a storehouse full of metal spears and javelins.
For ソウ, picture a soldier (ソウ) grabbing a metal spear from the storehouse: soldier -> ソウ, and the spear is ready for battle.