User blog comment:Evans0305/BioShock Infinite gameplay videos/@comment-2250991-20110712193309/@comment-2250991-20110712201348

Pauolo: I think it's like how in most games, you grab ammo out of a similar weapons. However, I did notice he didn't do the same for the RPG, so either it's a option to exchange weapons too low on ammo, or it works like L4D or Halo where it'll automatically refill with that weapon's ammo without needing the animation of grabbing it.

Wikia contributor: that's kinda what I meant. You can see him getting those similar weapons, but you don't see him constantly changing the same gun everytime.