cannon, gun
砲 centers on large projectile weapons: cannons and guns. It refers to artillery pieces that launch heavy shot.
砲 combines 石 (stone) with 包, which likely contributes the sound. Historically, early cannons used stone projectiles, so the stone radical fits the weapon meaning.
The left side is stone 石, and the right side 包 looks like a wrapped bundle. Imagine a cannon wrapped around a stone ball, ready to fire.
For ホウ, picture a cannon firing with a loud 'hou!' sound: the boom echoes ホウ as the stone ball flies out.
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gun; cannon; artillery; ordnance
firing; discharge of gun
(large) gun; cannon; artillery
bombarding; shelling; bombardment
gun; firearm
gunfire; fire
main battery; main armament
gun turret
shell; cannonball
(gun) battery; fort
water pistol; squirt gun; water gun
artillery; gunner
empty gun; gun loaded with blanks; firing a blank
rash; reckless; headlong; foolhardy
huge gun
gun barrel
gunshot; bullet
gunner
guns; firearms
flash flood