INF eventually intends to include body armor, and bleeding. Once these features are in the game then it will open up the doors for more weapons because different weapons and rounds have different effects on body armor, or the lack of it.
FN's P90 and 5-7 for example, are planned, as well as a HK MK23 .45 Socom with optional lam/supressor.
As far as i know, no new riles in different calibure's are planned at this time. The difficulty at the moment as i mentioned is the lack of body armor. Presently both a 5.56 and 7.26 will kill in aprox. 2 hits to the body.
If body armor and bleeding were implimented, the 7.62 round would have better penetration, and since it actually does more damage you'd probably die quicker from bleeding as well.
But at the moment there's little difference between the rounds, and since the #1 priority is to keep the game balanced, automatic, or even semi automatic 1 hit 1 kill weapons have no place in the game.
boom