The thing is though, that crunch on numbers? It's totally within the game's structure to have you decide when the players are low on ammo, or out entirely. I mean, using Click Click is one thing, and I will damned well use it because it's awesome, but - "OK, so that last fight left you guys really depleted on ammo. You could probably only make it through a maximum of 3 rounds of combat before your weapons are out of ammo, barring any despairs" is a legitimately easy way to cover it without crunchy numeric values for each weapon type. That way it's at GM discretion, and more importantly, it's very aligned to the narrative structure.

One more thing: i guess somestimes the GM could tell to the player "Hey John, you know you are running out of ammo" just like an advertise to remember that soon, with 2 or 3 threaths, the ammo will finish. It could help the player to think about the next steps.

So, we gave it a run through. "Click Click" is definitely the way to go for us. We're doing a hero's 'heroing in the grey' type of campaign. They can't really trust anyone, even the people they originally work for so supplies are iffy. Sometimes they're fully stocked, sometimes they'll be on the run for days / weeks. We did some minor modifications so it would feel 'right' for us, and I figured I would share.

Starting out:

Despair: While you're not out of ammo, the ammo you have is training ammo or something awful like that! Maybe a 12G with all Birdshot. Or FX rifle rounds, big boom, no projectile.

After each fight, you move down the "Ammo" ladder:

1 Fight: 3x Threat to "Out of Ammo". You were spraying bullets LITERALLY EVERYWHERE.
2 Fight: 2x Threat to "Out of Ammo". You held the trigger down a good deal. Time to restock the magazines.
3 Fight: 1x Threat to "Out of Ammo". Even the best trigger discipline runs out of magazines at some point.

Minions (and the environment surrounding the fight) have enough "spare" to reset 1 player per group of minion. Rival fights (along with their henchmen) have enough "spare" to reset 2 players. Nemisis Fights, typically, will have enough to restock the party. And as others point out, it's CRUCICAL that the GM's use of "Out of Ammo" makes sense. Fast and Furious, rumble tumble, you're fighting a chase and escape battle through a mall, a parking garage and then the city streets, sure. If you're lining up a single shot to open the combat from a concealed position with a brand new weapon, don't do it. It's not cool. lol

I'm sure I'll tweak it a bit more as we dive in, but so far, it felt 'okay' and no one was pissed off when it hit them.

Edit: We also created "Ammo Supply" as an item. Resets you back to 0 Fights.

I was Thinking what if for some guns/themes had an activatable attribute that would allow you to have more shots. you would be assumed to be out of ammo after you shoot unless you spend advantage(s). it could be called something like "Did he fire six shots or only five" or I still have more shoots around here somewhere. (I'm not very good at names)