Mass Effect 2 Can't Switch Sniper Rifles

The Incisor Sniper Rifle appears twice in my weapons menu in the game, sometimes one will have more ammo than the other but the one with the least ammo is always the "real" one.  I tried to change it in the menu before a mission, and it still gives me two Incisor Rifles no matter what I select.  I picked up the Widow Rifle on the Collector ship, and it still wouldn't switch from the two Incisor Rifles.