Back in the old days, our adventurers would delve into a dungeon with a limited supply of oil flasks, arrows, rations, metal stakes, and other consumables, marking them off our lists as we used them. These days it's just as likely that we'll be playing a game where we have a generic quiver of arrows, quantity of "adventuring gear", or collection of rations, where we don't specifically tracks individual expended units, but might instead roll a die to see when we have exhausted out supply.
The person whose comments reminded me of this concept, indicated that they thought it was silly that a character might give away their last ration to someone, not realising it was their last ration until the die roll specifically told them it was...and this was one of the things they hated about the game they were referring to. It seemed a valid comment to make, but I think it actually shows more of a fundamental difference in the way games are played more than a flaw in the design of a specific game.
Some might call it a flaw in the way of thinking about games, some might just say that it's different horses for diffent courses. We could dig make into that Forge game theory can of worms, where everyone has different interpretations of the underlying issues...but for the sake of this paragraph, the gamist tracks every bullet for the sake of getting the highest damage and most impact from every single bullet, while the narrativist really doesn't care unless a lack of bullets is interesting to the story, and the simulationist may vary depending on the genre they are emulating.
The gunfight at the beginning of Deadpool makes every bullet count, and it wouldn't make sense to simulate this in game with an abstract die roll after each shot to see it that was your last bullet. The bursts of gunfire from the Colonial Marines in Aliens, might be more appropriate for abstraction..."you've rolled poorly on your ammo die, drop from high ammo to low"..."you've rolled poorly again, you're spent"..."you've deliberately fired off a long burst, don't roll, just drop to the next lower ammo category".
In "The Law" I deliberately followed that second route because it seemed easier to simply allocate negative traits of "low ammo" then "no ammo" to a firearm. Such traits could be eliminated by spending an action to swap out an ammo clip. It basically works on the assumption that the Agents of the Law have plenty of access to ammunition and supplies, but doesn't reflect the possible desperation of a scene where ammo is a limited commodity.
I generally don't like the idea of using different resolution mechanisms in an ad hoc manner, so that leaves me with a tough decision about whether to completely change the game to a bullet-by-bullet system (where a burst might do extra damage in exchange for more wasted bullets)... or just leave it as is.
At the moment, tracking ammo clips specifically, but bullets abstractly seems a decent compromise.