Source: https://github.com/liurui39660/PayDay2.Mod/tree/BetterFullyLoaded

Basic: +ammo, +pickup. Ace: 3s arrow/throwable, 5% rocket/recharge.
Renamed from Fully Loaded Aced Always Grant A Throwable (3s Cooldown), so delete that mod first.
Throw the decompressed folder to mods/, like most other mods.

This mod gives Fully Loaded a buff. Below is the in-game description.

Basic: Your total ammo capacity is increased by 25%.
Also, the amount of ammo you gain from ammo boxes is increased by 75%.
Note: Does not stack with the perk deck skill "Walk-in Closet".

Ace: You get a regular throwable and an arrow from an ammo box. This can not occur more than once every 3 seconds.
You gain a 5% chance to recharge a throwable or get a rocket from an ammo box.
Note: This effect is triggered after successfully picking up an ammo box. Chances are computed independently.

Q: The in-game description looks a bit weird.
A: SuperBLT has some issues in parsing macros, use Localization Macro Replacement before they fix it.

I only did some basic tests. Please tell me if there's any inconsistency with the description.
Comments and suggestions are welcomed.