The problem with having Breakable Weapons (or non-Bottomless Magazines) is that, if you run out of weapons, the game becomes practically Unwinnable. To work around this, many developers are nice enough to give you a weapon with unlimited ammo to use in case of emergencies. It may not be as flashy or powerful as your main arsenal, but it's there when you need to get out of a jam.
Often, this [...] [tvtropes.org]