Big Guns

Big Guns is a Fallout, Fallout 2, Fallout 3, Fallout: Brotherhood of Steel, and Fallout Tactics skill. It determines combat effectiveness with any weapon categorized as a "Big Gun", such as flamers, miniguns, missile launchers, Fat Man, etc.

Fallout

 * $$\text{Initial level}\%=10+\text{Agility}$$

Example: A starting Agility of 5.
 * $$10+5=15\%$$

The Strength requirements of most big guns, combined with the weight of the guns themselves and the large amounts of ammunition they require make investing into Strength points at character creation a prudent choice for players planning to use these weapons as their mainstays. Most, if not all, big guns in Fallout are burst weapons exclusively, meaning that players cannot make targeted attacks with them. This makes taking the Fast Shot trait a much more viable option for big gun enthusiasts, as they enjoy the benefits of the trait without the drawback.

Affected weapons
Fallout Big Guns skill weapons, 2

Fallout 2 and Fallout Tactics

 * $$\text{Initial level}\%=2\times\text{Agility}$$

Example: A starting Agility of 5.
 * $$2\times5=10\%$$

As with Fallout, Big Guns operates in much the same way in Fallout 2 and Fallout Tactics.

Affected weapons

 * Fallout 2
 * Avenger minigun
 * Bozar
 * Flamer
 * Improved flamer
 * Light support weapon
 * M60
 * Minigun
 * Rocket launcher
 * Vindicator minigun


 * Fallout Tactics

Fallout Tactics Big Guns skill weapons, 2

Fallout 3

 * $$\text{Initial level}=2+(\text{Endurance}\times2)+\left\lceil\frac{\text{Luck}}{2}\right\rceil$$

Example: A starting Endurance of 5 and Luck of 5.
 * $$2+(5\times2)+\left\lceil\frac{5}{2}\right\rceil=15$$

As this skill increases, so does the accuracy and damage with all of these weapons, both in and out of V.A.T.S. mode.

Ways to increase Big Guns skill

 * Permanent
 * Leveling up (10+INT (+3 with Educated perk))
 * Bobblehead - Big Guns (+10)
 * U.S. Army: 30 Handy Flamethrower Recipes (+1 or +2 with Comprehension)
 * Size Matters (+15 with each rank, max 3 ranks)
 * Tag! (+15)
 * Temporary
 * Buffout (+2-6 depending on Endurance, a perfect Endurance of 10 will see no benefit.)
 * Linden's Outcast power armor (+5)
 * Torcher's mask (+5)
 * Raider blastmaster helmet (+5)
 * Bombshell armor (+10) (The Pitt)
 * Lag-Bolt's combat armor (+10) (Broken Steel)

Affected weapons
Fallout 3 Big Guns skill weapons, 2

Fallout: Brotherhood of Steel
While the game doesn't have the ability to increase the effectiveness of big guns, there are some weapons that are listed as such.

Affected weapons

 * Flamethrower
 * Heavy machine gun
 * Home-made rocket launcher
 * Incendiary mortar
 * Meat cannon
 * Minigun
 * Rocket launcher
 * Shredder