Placing a smaller gauge or caliber cartridge into a gun( such as a20 gauge shell in a12 gauge shotgun) can result in the smaller cartridge falling into the barrel and acting as a bore obstruction when a cartridge of proper size is fired.

• 如果误将小号或小口径弹药装入枪内（如将20%23弹装入12%23弹枪）结果会造成小子弹滑入枪管，再装填合适的子弹射击时就会造成堵塞。