Installation:

In File Explorer, navigate to Steam > SteamApps > common > MGS_TPP > master > 0. In there, you'll find a "00.dat" file. Move that somewhere else to keep as a back up and to merge with mine if needed. If you've never used a mod that had you replace or do anything with your 00.dat, go ahead and put the included 00.dat in this download into your "master" folder (where you found the other 00.dat that you just moved). That's it - you're done. But if you're using a modded 00.dat(*), you'll need to unpack it with MGSV QAR or another tool of your choice, open the "Lua Files" folder from this download, choose an option, and throw my "Assets" folder into your unpacked "00" folder. Repack, and use that new 00.dat. If you don't know how to do that, download MGSV QAR (you can get it on the Nexus) and give its Readme a look; it explains unpacking and repacking.

* - If you're using a modded 00.dat with a modded EquipParameters.lua under the same path as mine in my "Lua Files" folder, skip to the Customization section, or else you will lose the changes of the other mod that modified that file. If you're unsure which mods do this, suspect mods that change suppressor durability, ammo count, weapon sway, and/or penetration, as well as item count if using infinite items.



Customization:

If you want to change your own .lua files to add in unbreakable suppressors or other edits, you'll need a program like Notepadd++ to edit them. This section is also helpful if ever a game update causes the mod to fail (again) or you're using a mod that uses the same .lua's as mine. Here are some instructions on how to recreate each part of the mod.

-Suppressors
In 00 > Assets > Tpp > level_asset > weapon > ParameterTables > parts > EquipParameters.lua, search (Ctrl + F) for the phrase "muzzle". You should be taken to a section called "muzzleOptions". You'll notice every entry ends with three numbers. The first is a recoil multiplier and is usually either 1 or something around .8 (hence muzzle brakes, compensators, and the like). The second number is durability, and most suppressors will have numbers like 15 or 30 or 60. For infinite durability, change those values to -1. I haven't tested the third number, but I suspect it just changes whether the muzzle option suppresses shots or not.

-Ammo
In 00 > Assets > Tpp > level_asset > weapon > ParameterTables > parts > EquipParameters.lua, search (Ctrl + F) for the phrase "magazine" and you'll be taken to a section of the file with a (rather long) series of entries, each containing two numbers near the end, separated by a comma. The first is the magazine capacity and the second seems to be total ammo capacity (reserve ammo + loaded ammo). For every entry, change the second number to 0. I know, it makes no sense. But it works. If you only want to change the ammo for specific weapons, you might be able to tell which entry corresponds to which in-game magazine by looking at the ammo type and ammo numbers for clues. The entries also seem ordered somewhat as they are in the Development and Customization menus, with handguns first, followed by submachine guns, and weapons slung over your back like sniper rifles and machineguns later. If you're feeling adventurous, maybe change some of the first numbers instead of the second, and see if you can get a bottomless magazine if you set it to 0 or -1.

-Support Weapons
In 00 > Assets > Tpp > level_asset > weapon > ParameterTables > EquipParameterTables.lua (note that this is a different file than the one used for suppressor and ammo edits), search (Ctrl + F) for the phrase "SupportWeaponParameter". Each entry tells you what item you're editing (though the names differ from the in-game names) and has a couple of number values. The first is the item amount. For each entry, change this first number to -1 to get infinite support weapon capacity, else change it to whatever you want. I haven't looked into what the other numbers do, but take a look and maybe you'll see a pattern.