This question is NOT about whether any of these stack. I've read enough to know that they do not.
This question is to compare and contrast these 3 to make sure I have a full understanding of them, and not misinterpreting anything.
I've searched and read many threads on this. I've also tried searching for threads that directly compare these, but haven't found any. Many people compare Dead Shot with Vital Strike. But I disagree, I think Dead Shot is more of a variation on the Clustered Shots feat, and noting at all like Vital Strike.
So if I understand correctly...
Vital Strike adds ADDITIONAL damage dice (or x2 or x3 damage dice with Improved/Greater) for a single attack action (being a standard action). I.e., it does extra damage that the player wouldn't otherwise have.
Dead Shot and Clustered Shots do NOT do any ADDITIONAL damage beyond what the player would have in a normal full attack. At a basic level, they both pool damage from what is essentially multiple attacks during a full attack action. The idea with both is to create a single larger damage potential to overcome DR vs. smaller damage separate shots each having to overcome DR individually, but neither Dead Shot nor Clustered Shots do any additional damage beyond what would happen in a normal full attack action if there were no DR.
My guess of why people think Dead Shot is like Vital Strike, I think it comes from this clause in the Dead Shot description:
"For each additional successful attack roll beyond the first, the gunslinger increases the damage of the shot by the base damage dice of the firearm. For instance, if a 7th level gunslinger firing a musket hits with both attacks, she does 2d12 points of damage with the shot, instead of 1d12 points of damage, before adding any damage modifiers."
This is similar to the mention of damage dice in Vital Strike. But I think people are misinterpreting this Dead Shot description, and I think the example provided for Dead Shot is a poor example. By "increases the damage of the shot by the base damage dice", it doesn't mean you actually get extra damage dice that you wouldn't normally have. It just means you get the normal damage dice from THAT attack roll, the same as you would normally get anyway during a full attack action with multiple attacks. Just as if the attack roll is not successful, you don't get the damage dice for that attack roll. And a better example would be something like, if a 17th level gunslinger firing a musket hits with 3 attacks and misses with 1 attack, she does 3d12 points of damage, instead of 1d12 points of damage, before adding any damage modifiers." If the interpretation were similar to Vital Strike, the result of that example would be 5d12 (1d12 for each hit + an extra 1d12 for each successive successful attack).
Based on the above, that's why I say that Dead Shot is a variation on Clustered Shots (they both pool normal damage, not do additional damage), and not like Vital Strike at all. (Unless I'm the one interpreting that clause of Dead Shot incorrectly.)
The differences between Dead Shot and Clustered Shots are...
Clustered Shots pools a truly full attack action. Extra attacks from Rapid Shot & Haste would also apply. It also pools all BONUS damage from EACH successful hit. Each individual attack can crit on it's own.
Dead Shot is technically a single shot, thus using only a single ammunition, but still requires a full round action and still rolls separate attack rolls "as if she were making a full attack", just like Clustered Shots. Dead Shot only allows the base attacks "based on her base attack bonus," it does not allow extra attacks from Rapid Shot/Haste. It pools damage only from the base damage dice. Bonus damage is only added once after adding all of the base damage dice together. There is only 1 crit confirmation, either it all crits or none of it crits.
It also seems to me then that if one took Clustered Shots, the Dead Shot deed would be useless, except maybe to save ammunition. And Clustered Shots should do more damage overall since it also pools bonus damage, and allows extra shots (Rapid Shot/Haste).
So am I correct in my interpretations of the above? If not, what am I wrong about? (Does Dead Shot actually add an ADDITIONAL damage die for each successful attack?)
Your interpretation of Dead Shot is correct, you only get the damage dice you'd normally have from making an extra attack.
I agree that Clustered Shots is almost a straight upgrade over Dead Shot. The only downsides are that Dead Shot will do more damage if you successfully crit the target, and that you need Point-Blank Shot and Precise Shot to take Clustered Shots (although considering those are considered mandatory feats for a ranged character, that's not really a drawback).
A question: In the case of clustered shots, what happens if you use different ammunition for each shot? Say, one silver bullet, one +1 bullet, one good-aligned bullet (say from the rose warden's holy thorns ability) and one regular bullet? How would one expect the aggregate to affect, say, a common rakshasa or a star monarch?
Any further thoughts from anyone on this? Even if I'm correct, I'd like further confirmation, and also maybe people will see this thread and STOP saying that Dead Shot is like Vital Strike. I just read it again in somebody's Gunslinger Guide.
I was just so baffled at how many people said that Dead Shot was like Vital Strike, and I keep thinking, "no it's not, it's a stripped down Clustered Shots."
I even saw a post in ONE thread where somebody did compare Dead Shot to Clustered Shots, and somebody else replied "no, it's more like Vital Strike," but gave no reasoning. And I'm thinking to myself "NO, it's NOT like Vital Strike, the first guy was right." But that thread was several years old so it wasn't worth replying to now. :)
blaphers, sorry, I don't know the answer to your question. It's kind of out of scope for my original question. Maybe try posting it as a separate question if you don't get any other answers here.