User:KaiserYoshi
Will be using this page to compile some useful information.
Ammo consumption
Ammo conservation chances are not additive (20% + 20% ≠ 40%), they are multiplicative. The formula for finding total ammo conservation chance given n number of individual chances is:
| Ct = 1 - ( (1 - C1) × (1 - C2) × (1 - C3) × … × (1 - Cn) ) |
As an example, the Hallowed armor with ranged headpiece gives a 25% chance to save ammo, and the Ammo Box gives a 20% chance. These do not add to 45%; they multiply as follows:
| Ct = 1 - ( (1 - 0.25) × (1 - 0.2) ) |
| Ct = 1 - (0.75 × 0.8) |
| Ct = 1 - 0.6 |
| Ct = 0.4 |
| Therefore: |
| 25% × 20% = 40% |
If we then add an Ammo Reservation Potion to the mix:
| Ct = 1 - ( (1 - 0.4) × (1 - 0.2) ) |
| Ct = 1 - (0.6 × 0.8) |
| Ct = 1 - 0.48 |
| Ct = 0.52 |
| Therefore: |
| 25% × 20% × 20% = 52% |
This is with a normal gun. The Megashark, Gatligator, and Chain Gun have an extra 50% chance:
| Ct = 1 - ( (1 - 0.52) × (1 - 0.5) ) |
| Ct = 1 - (0.48 × 0.5) |
| Ct = 1 - 0.24 |
| Ct = 0.76 |
| Therefore: |
| 25% × 20% × 20% × 50% = 76% |
The more chances you stack together, the less of an impact each individual chance has. This means that it is completely impossible to have a 0% chance to consume ammo. Anyone who tells you that you can have infinite ammo with a specific gear/buff combination has experienced a research malfunction.
Ammo bonuses affect all Ranged Weapons, as well as the Flare Gun, Clentaminator, and Confetti Guns.
It is periodically reported that armor can only give one bonus. This means that though the Chlorophyte Helmet and Shroomite Breastplate both have their own 20% chances, they will not stack to 36% and you will have only a 20% chance if you wear both. If true (confirmation needed), this puts the full Adamantite and Hallowed sets, and the Vortex Breastplate, as the best ammo-saving armors on the PC version, and the Titan armor as the best on other versions.
Speaking of the Titan armor, this set induces some fridge confusion in combination with the above rule. Each piece of the set has its own 5% bonus, and the set bonus is 28%. If an exception is made for the Titan armor and all pieces are allowed to apply their bonuses, then the total bonus comes to 38.269%. If only one is applied, then the bonus is 31.6%, and if the set bonus overrides the individual bonuses entirely then it is just 28%.
Ammo bonus sources
| Item | Bonus | Notes |
|---|---|---|
 Necro armor
|
20% | |
 Cobalt armor
|
20% | Set bonus with Mask |
 Mythril armor
|
20% | Set bonus with Hat |
 Adamantite armor
|
25% | Set bonus with Mask |
 Hallowed armor
|
25% | Set bonus with Helmet |
 Titan armor(Old-gen console and 3DS versions)
|
28% - 38.269% | See above |
 Chlorophyte Helmet
|
20% | |
 Shroomite Breastplate
|
20% | |
 Vortex Breastplate(Desktop, Console and Mobile versions)
|
25% | |
 Magic Quiver
|
20% | Arrow-firing weapons only |
 Ammo Reservation Potion
|
20% | Lasts 7 minutes |
 Ammo Box(Desktop, Console, Old-gen console and Mobile versions)
|
20% | Lasts 10 minutes |
 Minishark
|
33% | |
 Gatligator(Desktop, Console, Old-gen console and Mobile versions)
|
50% | |
 Megashark
|
50% | |
 Chain Gun
|
50% | |
 Candy Corn Rifle
|
33% | |
 S.D.M.G.(Desktop, Console and Mobile versions)
|
50% | |
 Vortex Beater(Desktop, Console and Mobile versions)
|
66% | |
 Phantasm(Desktop, Console and Mobile versions)
|
66% |