I get the impression that a sneak attack critical is like a double critical hit. In other words, the attack is automatically considered a critical and then the damage is doubled on top of that. Is this accurate? Thanks.

Yes. Thus the Abeline BB Gun can, with a critical-chance/hit based build, actually be useful.

Yep - and if you hit them in the head it gets doubled again! That is why the sniper is the strongest play style in the game. Basically you get 8 times the damage of a normal shot.

Luck and critical chance is not a factor then doing sneak attacks as you always do critical. With silenced weapons you might get multiple critical hits, so better critical perks and weapons with high critical damage work best.

One feature in fallout 3 was that some shotguns did critical damage for each pellet or beam then not used in VAT making them do insane damage.

So, I'm still confused. Does the sneak attack double the total damage (reg + critical) or does it automatically just give you the critical damage.

YES.

"Sneak Attack Critical" message on screen = (gun base damage, say 40) + (gun critical hit bonus damage, say 30) x (2)

If I understand it correctly the way it works is you have Base Damage then you have regular Critical Damage on top of that. Your chance to get a regular critical is based off of your critical chance (based off of Luck and a number of traits, perks and any items you're wearing or if you're under the effect of a True Police Stories skill book) times the individual weapons Critical Chance Multiplier. For example if your base critical chance is 20 and you use a sniper rifle with a 2 x critical chance multiplier you get a 40% chance for a critical hit. If you use the Ratslayer with it's 5 x multiplier you have a 100% chance for a critical.

Most weapons critcal damage is the same as their base damage so you get twice the damage. Some weapons the critical damage is less than the base damage (ie the Anti-Material Rifle) while otheres the critical damage is much higher such as the Gobi Campaign Rifle and Abilene Kid bb gun.

In any case, once the base and regular critical damage are calculated this number is doubled on a Sneak Attack Critical. So if you fail the check for a regular critical you'll get the weapons base damage multiplied by two. If you succeed on the regular critical you get the base damage plus the critical damage and that combined number is doubled. So, using the Gobi Campaign Rifle (100 weapon skill, weapon in good repair and no damage threshold to reduce the damage) as an example, it's base damage is 48 while it's critical damage is 80. If you make a successful critical then a successful sneak critical on top of that it does 256 damage.

Now someone further up the thread mentioned you get another double if you shoot the head but I don't believe that's correct. My understanding is that it's just that the head has the fewest number of hit points so it takes less damage to get a kill with a head shot. If anyone knows which of us is right could you please confirm.

I believe you are both incorrect. Somewhere around here right around release, Josh said that the head shot multiplier was still in the game, but he reduced it to +75% dam. Not 100%. So a sneak crit headshot does 275% of (base damam + crit damamge). I'm pretty sure that's the formula. I think I verified it once, but if I get a chance later today, I'll double check it to make sure.

OK. Here's the data:

Weapon: 9mm pistol
Damage: 10
Critical hit damage: 10?
Target HP: 200
Target DT: 0
Target HP after sneak attack hit to the chest: 141
Target HP after sneak attack hit to the head: 93
Regular sneak attack damage: 59
Headshot sneak attack damage: 107

Someone do the math. I go more boxes to move.

-gunny out.

Hm. So you're saying that a Sneak Critical is not an automatic critical hit then, only a doubling of damage. I thought while crouched/sneaking it was both auto-crit + the doubling, not just double "whatever damage you happen do." Everything I've read about NV sneak has indicated this, but could be everyone's wrong, too.

Sneak attacks are always crits. Automatic. Also, I forgot that I had Living Anatomy on when I did that little test above. The +5% dam screws the numbers a little. If I get a chance again later, I'll redo them.

-Gunny out.

So, to verify what I think I've gleaned from this thread...

A sneak attack will always be: base damage + crit damage, total up those two, and then double it. (ex: 10+10 = 20, x2 = 40)

That right?

Plus applicable perks and item effects. Those get added onto damage before multipliers. I believe DT is also subtracted before multipliers. I just got done hanging a cabinet at the new house, and I'm gonna take a pizza break. I'll try to do a coupla tests so we can figure this out.

-Gunny out.

Be sure to account for having or lacking the better criticals perk. I think you may have had it on your 9mm pistol data.

I don't think so. I used Test Subject #1, who's save is still in Doc Mitchell's house, and I don't think I added any perks to him. Makes for a nice clean test subject. I added living anatomy to easily check the target's health, being the forgetful dofus I am I forgot the +5% against humans. My targets were raiders in Josh's weapons test cell that I gave 0DT and 200HP. I just forgot the damn perk bonus. I'm off to run a few tests now.

-Gunny, sated on pizza.

I asked about better criticals because that 20dmg critical becomes 107 if its a sneak to the head. Thats a 500% increase sounds a little big. Maybe critical damage of the weapon scales faster with skill level, Abilene Kid LE BB gun would be the easist way to test that theory though.

OK, between slices of Papa John's pizza, I was able to get some clean numbers:

Weapon: 9mm Pistol
Guns skill: 100, no perks
Damage: 16
Crit Damage: 16
Target: Raider in testjoshweapons cell
HP: 200
DT: 0
Regular chest damage: 16
Regular headshot damage: 32
Sneak chest damage: 64
Sneak headshot damage: 128

Perk added: Living Anatomy, +5% damage to human targets
Sneak chest damage w/perk: 68
Sneak headshot damage w/perk: 135

So it looks like I was wrong. Headshots are not +75% like I though Josh had said. So here's the breakdown:

Sneak attacks - Always crit, (dam + crit dam) x 200%
Sneak headshots - Always crit, (dam + crit dam) x 400%
Perk damage multiplier is applied to regular and crit damage - (dam + crit dam) x perk effect (1.05) x sneak attack effect (x 2 or x 4 for headshots)

Does that make sense?

-Gunny out.

Critical hit = Weapon DAM + Hidden critical damage

Sneak-Attack Critical = (Weapon DAM + Hidden critical damage) * 2

Sneak-Attack Headshot Critical = ((Weapon DAM + Hidden critical damage) * 2) * 2

With 100 Guns skill, normal ammo and no other perks, the GCSR will do 256 damage on a torso sneak-attack and 512 with a headshot. Perked up and using HP ammo it can roll over 1,000.

46 ACP - That is how I thought it worked. Thanks for confirming. I was alittle suprise when I read about the 75% dmg.

So still - Sneak Attack Headshots > All. Heh, a AMR Sneak attack head shot should pull in 880 damage. Beats everything in the game.

Actually, Big Boomer on a sneak headshot outside of VATS when all pellets hit would do 960 dam without perks. But you gotts do it ouside vats and all 14 pellets gotta hit the head.

-Gunny out.

But what with Better Crits? I thought the shotgun crit dmg was not applied on every pellet? Plus, it is a whole lot easier to score a sneak attack-head shot with the AMR. WIth Big Boomer, you need some patience and a lot of skill!

Unless it's been fixed, shotgun sneak attack damage is only screwed up in VATS. Each pellet might only have 9 damage, and give 9 crit damage, but when all 14 pellets from Big Boomer hit a sheak headshot, that's a bunch. In VATS, you get the 14x9 regular damage, but only 9 crit damage. I haven't tested to see if it's still bugged like that or not. I'll look at it if I can. I also wanna see how much damage a sneak headshot with a missle launcher and a fatman do.

Edit: Results of some not so SCIENTIFIC! testing with sneak attack headshots:
Fatman - 997 dam
Missle Launcher - 322 dam
Annabelle w/HE - 410 dam
Tesla-Beaton w/max charge - 860 dam

And the VATS/shotgun crit problem seems to still be there. I had significantly higher damage outside of vats than in vats.
-Gunny out.

i thought explosive weapon didn't got sneak attack and head shot ，hope you can figure it out

They don't get crits, that I'm sure of. I'm not sure if they get sneak attack bonuses or headshot bonuses. I need to do more playing around. Explosives damage is so wacky, it's hard to get repeatable results.

-Gunny out.

Pretty sure explosives can crit, but they can not get a sneak attack or locational damage bonus.

yes ，but the critical damage is 0