Let's be honest, the ammo tab in the store gets the job done just fine and shows the ammo well enough.
HOWEVER.
It could be so much cooler! There are already several ammo boxes rendered in the game and they're cool when you come across them, but just a picture of the cartridges doesn't exactly inform the buyer.
My suggestion is really simple, take inspiration from IRL brands and make some box art for the ammo tab! Just a simple little picture will be more than enough and it could really help people SEE what the ammo works for.
Also, let's not pretend, it'll just look really freaking cool!
(If you wanna post art, go ahead, just make sure it's not gonna get the mods snooping around with torches and pitchforks)