Grenade (Frag)

Fragmentation Grenade is an explosive thrown weapon that appears in all Fallout games.

Fallout and Fallout 2
Fallout and Fallout 2 Standard Fragmentation Grenade. Most effective when used on groups. 

Fallout Tactics
Fallout Tactics Standard Fragmentation Grenade. Most effective when used on groups.

Fallout 3
The Frag Grenade is the first type of grenade you'll find in the game (check the first blue Mailbox as you come into Springvale from Vault 101) and is commonly carried and used by melee equipped Raiders and Super Mutants. While it's unlikely to kill you by itself it can do a lot of damage in one hit and has a high chance to cripple arms and legs. It's blast radius is small compared to grenades you'll get access to later (such as the Nuka Grenade or Plasma Grenade) but it can still be useful against multiple attackers if they're bunched together at a pinch point like a stairwell or doorway.

The in game physics for grenades are quite realistic which means throwing "up" a stairwell or hill means they'll most likely just coming rolling back before detonating next to you. The plus side is you can throw them through doorways or bounce them around corners to attack enemies you can't see. Be careful trying to throw them through windows though as, if they hit anything they'll bounce back at you.

Are You John Rambo?
Demolitions Expert: If you take all 3 ranks (+60% dmg bonus) of this perk and max out your explosives skill, Frag Grenades become more than just firecrackers. You'll be able to kill just about everything with 1 grenade. Simple frags become Super Mutant Kryptonite. They hit for 162 damage, and that's enough to outright kill regular Super Mutants (sometimes in groups of 2-3, like when they're behind sandbags), the Brutes and Masters take two grenades each, or one with a little small arms mop-up. Its easy to engage an opponent after bombing them because the first blast always seems to cripple their arms and legs, making them easy pickings. Crouching and questing for the Wired Reflexes perk is the only known way to increase V.A.T.S. grenade range as gunslinger and commando perk benefits don't seem to apply. Tap Outcast Casdin for the technology side quest if you're going to be a pull-the-pin-with-your-teeth styled Rambo character, you can buy cheap, nearly broken power armors and laser weapons from the merchants and trade them in for tons of Frags.

Defensive Strategies

 * You'll know a grenade has been thrown at you when you see a red circle with a pointer appear at the center of the screen. Your best bet is to run quickly away to get clear of the blast radius.  Ducking behind cover isn't always reliable as the grenade can roll past your cover and detonate right next to you.


 * If you see an enemy with a grenade in their hand you can target the grenade in VATS just like any other weapon. If you hit the grenade it will detonate and damage whoever was holding it. Even if the grenade isn't in the enemy's hand, like if you sneak up on an opponent with grenades holstered, you can still target and shoot them while on the belt. Sadly, you do not receive xp for these types of sinister trick-shots.


 * Grenades may also be shot while mid-air as VATS recognize them as a separate targets. This is extremely useful to protect friendlies who may be easily injured or killed otherwise.

Offensive Strategies

 * Frag Grenades in Fallout 3, despite what their name implies (frag as in fragmentation) don't send out any shrapnel. Instead they behave exactly like Concussion Grenades, anti-personnel devices designed to cause damage with explosive power alone. Therefore, especially effective in enclosed areas or close-range combat because of their minimized friendly fire risk (no shrapnel spray coming back at you).


 * They work at closer ranges than you might think, with an in game blast radius of about 10 feet you can safely bomb enemies as close as 11 feet away! Plasma and Nuka grenades have almost double the blast radius, beware.


 * Fallout 3 frags have a small blast radius so anything you can do to get the enemy bunched together by leading them to doors, hallways, stairwells or other pinch points will increase their effectiveness. Just remember to be wary about trying to throw upwards.


 * Grenades have a random chance to knock down opponents, and flip Radscorpions upside down. The player can then switch to firearm and hose down the helpless target (or just keep bombing it).


 * The distance the grenade is thrown depends on how long you hold the trigger. Don't just tap it unless you want it relatively close to you. It does not appear that it can detonate in your hand, however.


 * Explosions from grenades that land and roll typically result in single or double critical limb damage to the legs as the explosion comes from the ground up. Instant detonations are usually mid-air upper body impacts and typically cripple the head and arms.


 * Grenades have a relatively low AP cost for the damage they do but throwing them outside of VATS then following up in VATS with aimed shots to the weakest parts of the bodies is an effective alternative against groups.


 * Using a frag grenade on any enemy that can be frenzied (such as Robots, or Giant Ants) has a relatively high chance of triggering it. Fire Ants are especially susceptible to causing riots among themselves, as they have a ranged attack.


 * Excellent against Mirelurks in general, but especially when they're submerged (Dynamite Fishing). Its almost impossible to miss, when the grenade hits the water it gets trapped a few feet under the surface. There's also a very satisfying water plume styled explosion.

Instant Detonations

 * "Cooking off" is a term referring to intentionally holding onto an armed grenade after the pin has been pulled and the handle released, to decrease the amount of time to detonation after throwing. This technique is used to reduce the ability of the enemy to take cover or throw the grenade back. It is also used to allow the grenade to burst in the air over defensive positions. This technique is inherently dangerous, since fuses may vary from grenade to grenade. Because of this the U.S. Marines describe cooking-off as the "least preferred technique", recommending a "hard throw, skip/bounce technique" to prevent an enemy returning a grenade.


 * During a VATS shot the player does not have the option to aim at specific body parts however the player does gain the following ability: Grenades are judged to be perfectly "cooked" and will detonate instantly if you hit the target (actually connect with it). Additionally some throws that hit the ground may still detonate instantly if the grenade rolls into the target.


 * Take note: Outside of VATS contact is meaningless, a lobbed grenade may bounce off a target as grenades explode on a timer, they are not equipped with a proximity fuse.


 * Bigger monsters and close range targets end in instant detonations more frequently than smaller creatures and long range targets.


 * Fast moving targets (runners) seem be better tracked by VATS and that draws a lot of instant detonations too.


 * It should be noted that even on a 95% calculated VATS shot long-range throws rarely touch the target, however they usually land quite near, exploding a split-second later, often still doing full damage (except, as pointed out before, in steep terrain like a balcony, fire escape, cliff, or rooftop).

Bugs

 * There's a known (xbox360) bug with Deathclaws (please submit: have any other creatures been reported?). As perhaps the toughest wasteland creature in the game a Deathclaw can survive a direct blast. There's a small chance of the explosion launching it far into the air, which is fine, if a bit comical, for a single targeted throw, or when fighting in real-time, but can cause trouble for multiple queued VATS shots as all following throws waste grenades and AP. Its probably best not to queue multiple-shots on Deathclaws, setup one targeted throw at a time. Or use the more common approach to fighting big nasties: Use one grenade to cripple it and mop up with small arms fire.

Weapons List
Granat odłamkowy