I usually just right it on a sheet of paper, but if that doesn't work for you, I suggest what Deadlands did. Make good sized bullet outlines on the side of your character sheets for the number of rounds in your primary weapon. Then use a paper clip to slide down the paper as you fire your gun.
Generally I always find it best to keep track of consumables that are used often on a separate page of notebook paper to keep the character sheet from getting worn out.
That's awesome. This may be an idea; I've been contemplating making new character sheets anyway and may add this feature "along the sides," kind of in boxes like a damage track. Thus, the player chooses their most "used" gun and weapon mode, marks how many bullets are shot in the graphic of the bullet/bullet hole, and slides the paper clip down when they fire. A gunslinger that commonly used two different guns could color mark the bullets or paper clips.
And I didn't really specify what I was talking about when I made the OP. Sorry about that. Also sorry I haven't checked on this question sooner. I'm actually talking about keeping track of bullets shot in their clips during combat; not purchasing and keeping track of regular ammo or specific AP or Gel round ammo. I re-read my original question and was like, "Really? That was really informative...facepalm."
Purpose of the question is that I'm a fairly new GM to the game; I've GMed all manners of D&D editions back in the day, a few WOD games, and one SR game. It was pretty simple. I'm easing my players into the rules, getting more complex as we play (for example, next time I'm going over when it's good to use a narrow/wide burst for gunslingers, magical lodge and counterspelling for the mage, charging and intercepting a charge for the ork brawler, and I'll do something else that benefits the specific characters for them soon) because you have to admit - until you get the hang of it, this game is extremely complex; and most of my players think so too. I'm also going to be going over actions; the first game was basic combat stuff, the second game they got in their first "real fight," but for their actions it was like, "What do you want your character to do," wait for an explanation, then "Ok, well of all that, this is what you can do. Yes, you can shoot him again."
But while I was getting the stage set for how I was going to present it, the tracking of firing ammo (normal ammo) until it's time to reload or etc, because if you ignore it, you're basically throwing away several key elements for simple actions (unload without a smartlink, reload). And we all love the actions in the movies when the hero, or in this case, anti-hero, runs out of ammo at the last second, to reload, jump into the fray and bury two bullets into the two antagonist goons trying to make him part of the wall decor.
But after typing all of that and commenting on the "bullet" tracker with a clip, that also means as a GM, I probably need to track it too, and the NPC's have much more options of weapons and amount of normal ammo per clip, etc. Any suggestions? Or should I just ignore switching out ammo in combat because it's too tedious to mess with while you're doing all the modifiers to determine your dice pool?