According to the Geneva convention and the laws of land warfare, can you engage and kill personnel with a shotgun?

Yes. Shotguns were never banned. And yes, it is legal to use .50BMG as an anti-personnel round.

BTW, the Geneva Conventions has nothing to do with the legality of weapons. That is the Hague Conventions. Geneva Conventions deals with the treatment of POWs, the wounded and civilians on the battlefield.

There are two relevant answers. The current doctrinal publication for the law of war is FM 27-10 (July 1956), because it is available on APD I will not post the text. para 34, b.

"The US DA PAM 27-161-2 (p. 45) quotes an opinion of the Office of the Judge Advocate General of 1961 stating that, while there is no conventional or customary rule of international law prohibiting the use of shotguns as such, international law does impose restrictions on the types of bullets that may be used in both smoothbore and rifled small arms. According to the author of DA PAM 27-161-2, the legality of the use of shotguns depends on the nature of the shot employed and its effect on a soft target: while the use of an unjacketed lead bullet is considered a violation of the laws of war, the use of shotgun projectiles sufficiently jacketed to prevent expansion or flattening upon penetration of a human body, and the employment of shot cartridges, with chilled shot regular in shape, is regarded as lawful."

I'm not a lawyer but your PSG asked you to look it up, reading FM 27-10 my interpretation would be yes you absolutely could engage and kill the enemy with a shot gun. And while we're here and I saw that "you shoot thier equipment" nonsense already, here's a couple exerpts from Stripes a few years ago regarding the M2 in particular and all weapons generally.

"Legend has it that the .50-caliber is so powerful that the Geneva Conventions prohibit U.S. troops from using it against human targets, but does that make sense considering it is okay to fire much larger artillery shells against enemy troops?

In truth, neither the 1949 Geneva Conventions nor other laws governing the conduct of war forbid U.S. troops from using the weapon (M2HB) against enemy fighters, said Gary D. Solis, an adjunct law professor at Georgetown University.

[This is the really important part]
Since all weapons issued to U.S. troops have passed a review that they comply with international law, .50-caliber machine-gunners can legally use the weapon against human targets, he said in e-mail.
[This is the really important part]

The exact origin of the rumor is unclear. Solis said it dates back to the Korean War, possibly earlier. Another story suggests that commanders in Vietnam were told to conserve their .50-caliber ammunition by only using it against enemy equipment or hard targets."

Most of this post is lifted from other sources, I hope you found it helpful and that you didn't just use RP as a crutch. Your ability to find "Army" answers to questions is important. When in doubt the Army Publishing Directorate is your friend.

I maintained a qualfication with the Remington 870 (military calls it the M870) and never heard of any restrictions or concerns about the Geneva Convention. We actually carried shotguns on our boat on Lake Huron instead of M16's due to some treaty or MOA we had with Canada about long guns. (The Canadian's frown on bullets bouncing around their shores, a.)

Where are you trying to go with this post?

Don't know, but why not? Just as fast.

I know of one type of weapon load that was in violation of The Hague Convention. This was not a shotgun round, but during the Vietnam conflict the M79 grenade launcher could be loaded with a "beehive" or flechette round and fired as an anti-personnel round as if it were a shotgun. Second-hand information - I heard combat veterans calling this their "alley-sweeper" round because of the effectiveness of the large number of projectiles. I was a munitions inspector stateside afterwards and signed off on the destruction of several of these rounds by EOD that had been kept as souvenirs when they were found in on-base barracks.

You can shoot his equipment and not the person I believe with any caliber. So as long as your aiming for his weapon or headgear your in the clear.

To the best of my knowledge - the Convention does NOT ban shotguns outright. However, there are munitions that are usuable with a shotgun that are NOT permissible - i.e. munitions that are not detectable with an X-ray within the human body.