KanjiJLPT N2
Bullet

bullet, twang, flip, snap

Mnemonic

A bow with a simple modification: instead of arrows, it fires a bullet. You pull back the string, lodge a bullet in the notch, and release. The simple elastic force of the bow launches it forward with a sharp crack, punching clean through a wooden target.
Additional thoughts
Visualize a primitive crossbow-like device—just a bow with a groove carved into it. Nothing complex, just simple physics launching a metal ball. The bow's snap is the origin of the bullet's flight.
Quick recall
A bow with a simple groove launches a bullet by bowstring alone.

Details

The keyword for 弾 is bullet. This kanji refers to a projectile fired from a weapon, such as a gun or cannon. Beyond its literal meaning of ammunition, it also carries the sense of springing back, rebounding, or repelling, as well as the act of playing a stringed instrument by plucking or striking its strings. These extended meanings all share the core idea of something being launched or propelled with force.
On'yomi
だん、たん
Kun'yomi
ひ.く、-ひ.き、はず.む、たま、はじ.く、はじ.ける、ただ.す、はじ.きゆみ