Anytime there is talk about hollowpoint (expanding) bullets everybody and his grandma is starting to mention "Geneva convention" which supposedly forbids the use of such bullets...
Let's put some things straight:
1. Geneva conventions are important part of humanitarian law, but they are not dealing with the use of bullets.
It's Hague convention of 1899 Declaration III.
2. First and foremost, it should be noted that said Declaration was adopted based on political conjecture (stemming from the development of the so (wrongly) called "dum-dum" bullets) and not on humanitarian grounds.
3. Declaration says: "The Contracting Parties agree to abstain from the use of bullets which expand or flatten easily in the human body, such as bullets with a hard envelope which does not entirely cover the core, or is pierced with incisions".
4. Stricto sensu declaration does not cover use of fragmenting bullets, although (imho) it could be argued, that use of such bullets falls into the scope of the Declaration (at least in spirit) because:
4.1. Declaration makes an appeal to the Declaration of St.Petersburg of 1868 which deems unwanted "employment of arms which uselessly aggravate the sufferings of disabled men, or render their death inevitable".
4.2. Fragmenting bullets before they fragment must deform ("expand or flaten") - there is no other way.
5. Bullets (M193 and M855) used in 5.56x45mm NATO caliber guns (which are standart in the NATO countries) do fragment on hiting the target (they are intended to fragment).
6. Because of that (points 4 and 5), imho, the rules set forth in the Declaration can not be considered part of customary international law (or customs of war) - you can not talk about the existence of the customs when nobody cares for them or acts according to them.
7. Declaration is binding only in the time of war - not in the time of peace.
8. Declaration is binding only for states which are contracting parties of declaration in the armed conflict between them.
9. Points 6 and 7 mean that Declaration has no effect what-so-ever on bullets used for self defence (and counter terrorism or peacekeeping operations).
10. It should be noted, that there is another Hague convention - Hague Convention of 1907. This convention did expand upon original Hague convention. Convention (Hague IV, Anex) inter alia states: "it is especially forbidden -
To employ arms, projectiles, or material calculated to cause unnecessary suffering" (please note, that the wording here is different from the wording used in abovementioned Declaration of St.Petersburg).
11. This rule is considered customary rule of international law.
12. Hague convention of 1907 does not include (verbatim or otherwise) text of the Declarations of the Hague convention of 1899.
13. "Unnecessary suffering" is a term which can not be satisfactory defined. Although from the look at the current state of affairs it seems that aforementioned NATO bullets, i.e. fragmenting bullets and bullets which wound by yawing (rotation) are not considered to be causing "unnecessary suffering"*.
14. Again, as was mentioned when talking about Convention of 1899, all of this is only apliccable to the war. Not peacetime. Not self defence.
[edit 20100924] Welcome, visitors from SayUncle :)
Further discussion on this topic can be found here.
* And I would agree with this assessment:
imho "unnecessary" in this context means "going beyond the sufering which is unavoidable when striving to achieve the goals". Bullets (when used in the war) should be at least effective enough to cause wounds which would remove wounded soldier from the action for a considerable time - 5.56mm diameter bullet which did not expand, fragment or yaw (rotate) would be totally unable to do that. Yes, such bullets would not cause "unnecessary suffering", but would be totally ineffective as a means of war (would not achieve the goals).