Sneak Attack Critical < onlyinclude > A Sneak Attack Critical occurs in " Fallout 3 " and " " when attacking while . Successfully hitting the target will result in a guaranteed critical strike ( unless the weapon does not allow critical hits ) , while at the same time doubling ( ranged ) or quintupling ( melee / unarmed ) total damage . < / onlyinclude > Sneak Criticals & slow projectiles . Certain weapons , like the microwave emitter , have relatively slow projectiles . Outside of V . A . T . S . this may sometimes give away the attacker ' s position before the shot reaches him , nullifying the Sneak Attack Critical bonus . For that reason , it is important to be close to the target before trying to Sneak Attack Critical , if using these weapons . Choice weapons . The best weapons for sneak attacks are the ones with the highest critical damage bonus ( affected by + 50 % damage Better Criticals perk ) . Here is a number of weapons with big bonuses . The number marked in bold is the critical damage when the Better Criticals perk is taken . ^ Damage calculated with Xenotech Expert " Damage calculated with the perks Pyromaniac / Xenotech Expert / Both Damage calculated if the weapon is fired outside of V . A . T . S . , and all pellets make contact . ( See below ) . Sneak Attack targeting in V . A . T . S . . For most creatures in the game , a sneak attack headshot , along with the Better Criticals perk , can be an instant one - shot kill on Normal difficulty or lower . ( Even the low - damage dart gun can kill raiders with one sneak attack headshot ) In some cases , however , it may not be possible to line up a headshot on a target , due to the target facing an unfavorable position or an obstructed line of fire . In these cases , even a sneak attack critical on an arm or leg can prove fatal to the target . Though results may vary based on the character ' s skills and perks , it is possible to shoot off a target ' s limb — an instant kill — with one shot from a sniper rifle . This may be a worthwhile consideration when chances to hit an appendage are significantly higher than head or torso shots . Multi - shot weapons . Weapons that fire several " shots " at the same time , such as combat shotgun s ( and The Terrible Shotgun ) , Metal Blaster ( from " The Pitt " ) , Protectron ' s Gaze , the tri - beam laser rifle ( from " Broken Steel " ) , and Paulson ' s revolver ( from " Mothership Zeta " ) are some of the most effective weapons for sneak attacks ( when done outside of V . A . T . S . ) . This is due to the fact that outside of V . A . T . S . , each of the weapons ' shots ' critical damage is calculated " individually " . This aspect makes these weapons very effective in sneak attacks ( and regular critical hits ) . With the right addition of perks , such as Better Criticals and Finesse , these weapons will be able to deal large damage consistently . Calculating the weapon ' s damage . The Terrible Shotgun is the best example for this concept . While in perfect condition , and with a Small Guns skill of 100 , the weapon deals 80 damage , with an extra 40 damage for critical hits . However , this weapon fires 9 pellets . Because of this , when the weapon is fired outside of V . A . T . S . and scores a critical hit , the critical hit for each pellet is counted individually . This means that ( if all pellets make contact ) , the weapon will deal " 440 " damage ( 80 base damage , plus 9 extra 40 critical damages ) . While sneaking , this damage is doubled , increasing it to " 880 " points of damage . In addition , if the attacker has the Better Criticals perk , the damage will increase to " 1240 " . If the damage is further increased via a headshot , then that damage doubles again to " 2480 " ! High enough to instantly kill almost anything in the game with a single shot . In " Fallout : New Vegas " . It is worth mentioning that in " Fallout : New Vegas " , most multi - shot weapons have had their crit damage significantly reduced . As mentioned , in FO3 , The Terrible Shotgun has a base damage of 80 and a crit damage of 40 . Compare to the riot shotgun in " Lonesome Road " , base 75 damage , but only 10 crit damage . Thus , on a full 7 - pellet - hit SAC , the total damage is 75 base + 70 critical = 145 total x 2 SAC multiplier = 290 . This is still enough to kill most enemies outright , but is significantly less than the previously illustrated 880 from the FO3 Terrible Shotgun . This is most likely a change implemented to directly counter the rapid " over - inflation " of critical damage as outlined in the previous sections . However , this also has the side - effect of lowering non - SAC critical damage , and more significantly V . A . T . S . criticals & SACs with multi - shot weapons . Because each pellet will only add 10 damage if it crits , in V . A . T . S . , a regular crit will only do 75 + 10 = 85 for a normal crit , or 170 SAC damage . These changes make crit % increases somewhat under - valued for characters using multi - shot weaponry .