I don't understand your reasoning. The shots the do most of your Piercing Shots damage (Aimed and Steady) both benefit from ArP. Without enough crit rating, you're not getting the full benefit from ArP because the big advantage of these shots is that they essentially get a 30% crit damage buff from Piercing Shots. Just saying that AP is going to scale linearly no matter what. Together, crit and ArP scale exponentially with each other due to the crit buff from Piercing Shots.

If you don't remember, Piercing Shots works like Deep Wounds in that the damage left from the previous application is added into the damage of the new application, so it doesn't matter if you keep it rolling or not

* Item - Hunter T9 2P Bonus - The damage done by your Serpent Sting ability can now be critical strikes.
* Item - Hunter T9 4P Bonus (Steady Shot) - Each time you hit with a ranged attack, you have a chance to grant your pet 600 attack power for 15 sec.

Source: MMO Champion

Dunno what that Steady Shot in the 4P means, but depending on proc rate and ICD it's probable that this will be skippable.

Is it worth to skip 600 AP for our pets? That is quite a huge boost for them, given that they don't have much AP to begin with, much similar to how Might is a nice buff to pets.

Don't worry about the word steady in there, Blizzard is just lazy and doesn't want to rename the spell, but we'll be getting 600 AP for pets for our 4P T9.

If it retains the proc rate/ICD of the t8 4pc then it's probably a slight upgrade simply because it procs off of anything rather than just our lowest priority ability.

That doesn't mean that it's irreplaceable, however.

Preface: I have 2 80 hunters, my main is about as geared as you can be except for cloak of Gen (never seen it in umpteen kills...), Trink off Big Al, etc.. (yes, I fail for not being a JC). My Alt is about average geared for a raiding hunter I would say.

I've been doing a lot of real world testing (on both hunters) with Arm Pen, rotations, talent specs, gems, etc, etc and here's what I've found for max DPS - *warning* some of my conclusions are opposite to what "math" and/or the spreadsheet tells you so take it or leave it... This isn't meant to be controversial, just helpful perhaps and these findings may not be true for your gear level.

- The spreadsheet is a good guide, in fact it's excellent, but not always correct.
- Testing on dummies is pointless unless you have full raid buffs.
- Gem/Gear for Arm Pen IF you have [Mjolnir Runestone] - Gem agi if you don't.
- Lose hit gear and spec 2/3 or 3/3 Foc Aim - especially get rid of gear with hit/haste
- Keep tier chest/head and use better individual pieces if you have them instead of 4-set [Mantle of Fiery Vengeance], [Saronite Mesh Legguards], etc... otherwise, 4-set is nice.
- Use Arcane Shot even if you don't talent for improved - I have not found a build where it hits for less than steady buffed or unbuffed, and it will always crit more than steady. If you get a ISS proc, skip Arc for Chim/Aimed. (I can hear everyone thinking, "yes, but the math, the spreadsheet!) See warning above...
- For one of your specs, spec 7/57/7 with 0/2 RF and 0/2 Rapid Recoup - put points in all other dps talents. This is for short fights or fights where your max dps only really matters for a short period of time. You'll be blown away by your numbers - try this on Patchwerk for example...
- For your other spec for longer fights or 10 mans, try 7/59/5 - if you don't or cant put points in Foc Aim, go a more standard 7/57/7. I swap 10 man hit cloak for aged winter in this spec to pick up 1% more hit.
- Put a point in Trueshot - even on tank n' spank fights, Ul rage/Abom might are not up 100% of the time
- I've found the top DPS rotation is to start serp, Chim, Arc, Aim then prioritize Aim over Arc unless you can start that rotation again, if you get my drift...
- Gemming Arm Pen kind of pigeonholes you, and on fights where SV is better, it's a handicap
- Change glyphs based on the fight - they are cheap... ex, Kill Shot instead of Hawk on Yogg, no brainer...

The 2-piece will obviously be a pretty powerful buff for all specs. Likely considerably more than T8-2 is. A raidbuffed T9 capable Hunter (to get the gear) should, even in the case of BM, be sitting at 45%+ crit.

And if we look at Mortal Shots it says
And then there is the metagem.

That's no mean difference. However, both MS and the meta might not apply since this is a gearthing, and as such talents doesn't always apply to that. Personally I think it just might.
This could mean a big difference in how Survial and BM would spec.

The 4-piece... Well for BM it is a considerable bonus. For MM and Survival it is at best nice. As Survival it is not rare to see my pet with 5000 AP. And even so it is hardly impressive in damage. Another 600 AP will not be markedly noticeable. And then there is the potential 15/45 uptime/ICD as there is with so many items.
Overall, better than the placeholder before, but not much more.

Yes, I know but the point of my post is that the max dps I am able to achieve in real boss fights is by using/speccing into arc shot...

One person's WWSes matter very little when you consider that our stats go into decimal points. It's entirely possible that your "max DPS" experimentation was simply skewed by RNG. Please do not tout it as factual, especially when it goes against traditional opinion and math. Display some numbers or theorycrafting of your own.

2 Set t9 looks incredible. Anyone know what type of dps boost we are looking at from serpent sting crits just from the bonus? It seems tons better then the 10% on t8..

Using two pieces of T8 and T9 would be incredible for MM. The serp sting dmg would be increased as well as crit, making the serp part of Chimera Shot hit like a freight train.

I don't believe the 2pc T9 would affect the Serpent portion of Chimera Shot.

Why not? The glyph of serpent sting works perfectly with Chimera(Serpent) damage.
The only thing that i am curious about is the crit rate on serpent sting.
If it affects 40-50% of ticks, i want it now

And one more thing, i also hope that Mortal Shots, and meta gem will affect serpent crits too

You are mixing up the 2 set bonus of T8 with T9 now; 10% extra damage on SrS (T8) did not affect the Chimera-Serpent part in any way, but that has been fixed a while back: Chimera-Serpent does benefit from the 2 set bonus T8 now.

As far as the 2 set bonus for T9 goes, i don't see how it could possibly affect Chimera-Serpent. Chimera Shot looks at the total damage of one Serpent Sting application, so that's 5 ticks unglyphed, 7 ticks glyphed. How on earth would the Chimera have to estimate how many of those ticks will crit? None may crit, or all may crit; i fail to see how Blizz can implement such a mechanic, or what calculations to base it on. As such, i think the 2 set bonus for T9 will 'merely' affect our Serpent Sting ticks.

I have a question about Chimera Shot - Serpent:
As I'm working on SimulationCraft etc. I wondered if the sim actually matched ingame behaviour (which it didn't in the first place, it double-dipped from target_debuff/player_buff)
CS-S damage should be: sting_tickdamage * 0.4 * ticks (= 5 unglyphed, 7 glyphed)
I went to a target dummy in TB and got (The World of Warcraft Armory my hunter, I unequiped trinkets with procs etc.)
Sting: 606-607 ticks => (*0.4*7 = 1696.8 - 1699.6)
CS - S: 1735-1740
I unqeuiped other items, but there was always a 2% difference between the expected damage and what it really did ingame. Did anyone every try to find out why there is this difference?

That's my rationale as well Pijn. The 2pc T9 won't increase the number of ticks nor the non-crit damage done per tick so it would be impractical to think that Blizz will calculate Chimera-Serpent based on your crit rating.

Ya, but just allowing Serpent Sting to crit, especially if Mortal Shots applies, will be quite a good dps boost. Even a pretty safe estimate of total damage being 6% from Serpent, thats still easily a 2-3% total dps upgrade with a ~45% crit rate.

I am not sure if I am at the correct place to ask help about this; but still think it should be OK. I consider myself quite heavily geared (Almost All Ulduar 25 gear) And the spreadsheet clearly indicates I should respec to MM (I am a dedicated SV and am much used to play with the shot priorities / instants etc) Also I tend to move quite a lot in Ulduar on fights (Hodir, General, Yogg)

My Problem is I tried to build my own MM build but I simply have huge difficulty in adapting to MM. (Need to shoot a new serpent + Hunters Mark every target change then shoot Chimera etc.) Is there some used shot rotation macros ? Or may be add-ons etc. To help playing marksman ? Or do I simply need to practice much to feel comfortable with it...

PS : I am afraid all the MM real bonus evaporates on much moving fights where I usually fail to shoot enough steady shots to benefit... Regardless of whatever spreadsheet says I feel as if SV would benefit me more on Yogg / General type fights.

MM is not bad when moving. You got 1 more instant than SV (Arcane instead of BA), and you haven't got Sniper training.
(And lot of the fight doesn't need too much running.)

Let's see the bosses:
Ignis, Razorscale, XT, Assembly of Iron, Kologarn, Auriaya, Mimiron, Hodir, Thorim, Freya: MM
XT Hard mode: SV, if you are killing the sparks (we do with 3 hunters), MM if you on the boss (As SV, I shoot HM, BA, SrS on the boss, and ExS, Aimed, SS on the sparks)
General Vezax: SV (You can do more dmg with lower AotV-time.)
Yogg-Saron: MM (if you are on Yoggi in the last phase, if not you can choose SV too, but I didn't used to.)

MM is relatively weaker then SV if you have to shoot lot of individual adds with little HP, because there is no time to achive full serpent dmg, no time to piercing shots.
If there is a lot of adds at a time, MM is better than SV because bigger volley-dps.
With pure 1-boss dmg MM is better, even when running (one instant shoot with low-CD instead of a dot with longer CD).

Fights that require a lot of movement do not murder MM dps as much as you seem to believe. Most of our damage comes from our instants, dots and auto shots; none of these should be affected by constant movement. (assuming you are stutter-stepping and are shoting instants while moving)
SS is an important part of our dps between ISS and its own decent damage with higher armor pen, but setting back one or two each rotation shouldn't cause survival to become more powerful on a single large HP mob.

While MM does rely more on SS and AutoS than SV, it really isn't that big of a difference unless you are moving very frequently or for long periods of time. A large number of our GCDs are still used by instant shots. However, if using the ArP spec without ArS, this problem could be exacerbated (which is why you should still keep ArS on your bars as ArP spec, and only use it on the run).

As for PS2, for any target that you really care about max DPS, you should always make sure a hunter's mark is up anyway; its 500 AP for you and every other hunter. If it's not worth the GCD to apply the +500 AP buff, then the small amount of damage you'll lose through the talents which require it is similarly negligible.

Both SV and MM gets about 35-40% of his dmg from Auto Shot + Steady shot. (SV closer to 35%, MM closer to 40%)
It is a surprise, but as I can see our logs, this is quite true.
(MM: 29% auto +13% Steady, SV: 25% auto + 12% steady)
(Get from one of our Ignis kill, same gear, Bené and Grakhar (me) got same skill, Eccs had soma issues with priority: World of Logs)
If you have to run, you lose this part of dmg, but as SV you lose another 6% from Sniper training. As MM you can use all your shots.
(Btw, I found that forget ISS and put points in IHM is a DPS-increase to personal DPS too, not just raid-dps, so my SS only procs T8,5 4-piece bonus which is the same for SV.)

For XT-hard-mode add-killing job SV is better, because as SV you lose most of yours "dot's" dmg (SrS, Piercing shot). As SV you can dot up the boss with BA and SrS, so you only lose the mdg bonus from it. (And can get LnL.)

HM is a big DPS upgrade to all the hunters. What I always to wanted to count that how much DMG I got when I put it up. For example does it worth to put up on a boss, if it dies in 30sec/1min/2min, or it's better to use the GCD for a shot. Did somebody make this kind of calculations?

There are a number of Addons that will help you get the MM rotation down: Watcher, EventHorizon, and FaceShooter by our very own Midnight. The rest is just practice.