For posterity I'm going to post this again, again much of it's eventually going in our Salamence writeup (this was originally aimed at Phuquoph in an early RMT of his):
When is AG Mence going to come in on Gyarados and not force it to switch? Only if it both did not Dragon Dance and it does not have Ice Fang. Take a look:
Adamant, 383 Attack Gyarados's Dragon Danced, Intimidated Ice Fang (normal attack) on a 332HP/196Def (4EVs/min) Salamence: 111-131%
Adamant, 383 Attack Gyarados's Dragon Danced, Intimidated Stone Edge (normal attack) on a 332HP/196Def (4EVs/min) Salamence: 85-100%
It is mere serendipity that the Adamant 341 Attack that grants the "magic stat point" (skipping from 339 to 341 with 4EVs for those of you who don't know what I mean by that), does, minimum, 99% with Ice Fang to the same Salamence, but that obviously doesn't matter since you are going to die over 92% of the time (taking into account Ice Fang's 95% accuracy) if you stay in on this relatively "weak" Adamant Gyarados. If it does not have Ice Fang, there is no way it's staying in on a Salamence that just switched into it, even if it DDed on the Salamence switch, because it is Intimidated. I guess you can bank on an opponent staying in to Stone Edge, which won't very likely KO unless you've taken previous damage, but I obviously wouldn't count on Salamence winning this battle in general.
In the only two Gyarados vs. Salamence battles that matter, due to the nature of "CBed" pokemon , it is using its AGed Meteoric Swarm, at full power, or its AGed Dragon Pulse in place of the hypothetical HP Electric. If it isn't clear to you why these are the only two scenarios that matter, listen closely — assuming Gyarados is at max or near-max HP:
If Salamence is locked into Hydro Pump, it is switching out.
If Salamence is locked into Flamethrower, it is switching out.
If Salamence is locked into a Meteoric Swarm (that's lowered its SpA to 262) it is switching out.
Otherwise, it is simple:
Modest, 350 Special Attack Salamence using an AGed Meteoric Swarm against 336HP/236SpD (fair/min): 100-117%
That's the spread I used in Advance, and, while I don't expect many people to go much lower than this, I likewise don't expect too many people to use the much bulkier Gyarados I would in DP, but I'll post those numbers too:
Modest, 350 Special Attack Salamence using an AGed Meteoric Swarm against 384HP/236SpD (near-max/min): 87-103%
I don't like Gyarados's chances. The other scenario is with Dragon Pulse, and here are those numbers:
Modest, 350 Special Attack Salamence using an AGed Meteoric Swarm against 336HP/236SpD (fair/min): 64-76%
Modest, 350 Special Attack Salamence using an AGed Dragon Pulse against 384HP/236SpD (near-max/min): 56-66%
You might be thinking I left out, in the heads-up two Gyarados vs. Salamence battle, the possibility you're locked into Dragon Pulse, which obviously doesn't OHKO. But that doesn't matter, and this is why — assuming Gyarados is at max or near-max HP:
If Salamence is locked into HP Electric, Gyarados knows you have HP Electric, and is dead, or is never, ever coming in.
If Salamence is locked into Dragon Pulse, either Gyarados is at, maximum, (assuming my bulky spread) 50% (assuming Leftovers recovery), and will be 2HKOed, or Salamence just killed a pokemon and is switching.
If Salamence is locked into Dragon Pulse, it does not have HP Electric, as they are mutually exclusive on a (good) AG set. I mention this to remind you that Gyararos can't both know you have HP Electric and still come in, and that, by the same token, know you have Dragon Pulse and feel threatened by the possibility of HP Electric.
If Salamence is not locked into anything, it will likely OHKO Gyarados with Meteoric Swarm.
I hope that's clear, as I've spent quite a bit of time laying out why it doesn't really make sense to have HP Electic on AG Mence. The only reason to have it is if you fear Gyarados form ever, ever coming in. And are you using HP Electric regularly to keep Gyarados from coming in if you kill something with it? I don't think so — besides the fact that your Starmie keeps Gyarados at bay especially with Wish Support, consider the other side of the coin. If you use HP Electric, and your opponent has figured out you have Adherence Glasses (which is about as likely, assuming an observant opponent, as you knowing they have a Gyarados that warrants your use of HP Electric in the first place), you are basically begging them to send in DP's most hyped pokemon in Gablias. You can switch to Starmie now, I guess, if you're so confident Gabby won't predict you and use EQ/DC instead of SD, (or possibly Sub) but shouldn't you already be using Starmie to stave off Gyarados threats in the first place, without necessitating the use of HP Electric on AG Mence.
Despite my tone and the volume of this insight, I'm not trying to strong-arm anyone into accepting things just because "I, the mighty Jumpman16," posted them. The numbers, though, literally speak for themselves.