The gun, ammo and magazine names should be adjusted to be more clear.
There are so many different kind of guns and magazines that it is hard to manage them. Often you find gun without ammo and store it somewhere. Or you find ammo without gun and store that too. Then you look at your storage to see what ammo fits to what gun and it is horrible mess. You can’t use the advanced inventory at all and instead need to use the normal inventory to look at each gun one by one to see if you have ammo for that or even magazines.
Simply having the caliber in the name would make it much easier to find and manage guns. You could even use the search then!
So for example "Glock 22" would be renamed to "Glock 22 (.40)" and the "Glock magazine" would be named "Glock magazine (.40)". Weapons and magazines that already have the caliber in their name probably don’t need it added second time.
Some names are also confusing. For example "Glock magazine" doesn’t go into Glock 22 but into Glock 19/17. So lets also speciy which glock the magazine is for and rename it to "Glock 22 magazine (.40)". After a quick look I didn’t notice other magazines with this kind of unclear names.
The .223/5.56 NATO is a mess. The game handles them as being exactly the same thing but the naming and weapon descriptions separate them. You look at weapons the description says it uses “.223” ammo. But when alll you find is ammo called “5.56 NATO” you will think you can’t use it. Then eventually you happen to look at the 5.56 NATO description and see that it is called .223 ammo there.
I would suggest renaming the ".223" ammo type to ".223/5.56 NATO" or ".223 or 5.56 NATO" and also to rename the ammo items to include the other caliber in their name. So ".223 Remington" would be renamed into ".223 Remington (5.56 NATO)" and "5.56 NATO M855A1" would be renamed into "5.56 NATO (.223)" (the “M855A1” is useless detail that does nothing but add confusion).
5.56 NATO is also usually called "5.56 NATO" except in ammo belt where it is called "5.56x45mm" adding more confusion.