Notice in the H1 pistol the mag extends over the handles edge. Also the scope is screwed on! Cap. Keyes says when he gives you it "Thats my pistol" so he obvisouly tweaked it for himself. The H2 pistol is the norm for all of the UNSC. Now as for the AR they upgrade it from the AR to the BR. Read Halo: First Strike it explains it.
mb its a totally different gun. H2 is black, and differently shaped. The scope on the H1 Pistol looks Integrated in. So I think its not that the Cretors got lazy and didnt add 2 kinds, they just different kind of pistol.
I have to dissagree with the 'infinate range' for pistols. They do have a distance over which you can't hit things. It's just past when the recticle stops turning red for a target. This holds true for both single AND multiplayer. And it's ballanced in singleplayer because they don't give you enough ammo to rely only on that. In multiplayer, it's a bit unballenced unless you know how and when to use it. and how and when it will be used. I honestly think that for multiplayer, there were some SERIOUS errors made in the weapons tweaks. The dumbing down of the pistol and spray-n-pray enforced by the omipresent smg are two of the major errors.