My son will be old enough to hunt deer next year and considering letting him use my dads old single shot .410, everyone ive talked to says .410 is unethical because of its lack of power. Im not thinking 100yard shots, like 50 yards or less. Ive found 1/5 oz slugs and 1/4 oz slugs. Thats right around 88gr-109gr, why would that be an unethical firearm with the right shot placement? Any insight would be appreciated.