what would be the BiS great crossbow for this build?

There's only 2 wisdom in enhancements in the great terror build fyi and no offhand slot available for great crossbow

I'm sitting at about 76 dc and don't seem to be getting any PK at all, I vorp and things trip but that's it.

"Shoot for 85-90 DC." theres about 85 available DC if you have everything and a 7 tome and 17 wisdom item so saying 90 is like saying 190.

*updated 3/4/2016


The GT, AKA: The Great Terror.

I developed this build to use the GxB's expanded AATerror range, GxB endless fusilade ROF, GxB's Large Base buffed by +4[w], mechanical reloader, Ranged Power amplified Sneak attack dice, and alternating IPS/Archer Focus to maintain heavy Mech DPS with very frequent DC88 insta kills.

The Build exploits the GxB Terror vorpal range of 19-20. By using the chain of: Endless-fusilade* 23 seconds Normal GxB fire*Endless-fusilade, it achieves a 37 second burst that produces a PK kill every 3.2 seconds at a DC of 87. During Endless fusilade itself the build produces a 7 second bursts of PK kill every 2.3 seconds or by running without any boosts a normal rate of 1 PK kill every 4.3 seconds. Of course running with and utilizing IPS properly will exponentially increase all those proc numbers as each additional target strike uses the doubled Vorpal range to PK twice as often. Also of note, if Manyshot is used 2nd during an attack chain the second Endless Fusilade can be started the moment Manyshot ends. The 1 second EF prep animation runs concurrently with the weapon switch, resulting in a quicker EF start as well.

Outside of PK kills, the running Mech DPS is high due to 14-17D6 Sneak Attack, +4[w]GxB, +16GxB Damage, 30% reloader speed, Mech tree ranged power, expanded Vorpal and the Runearm damage, scaling Runearm primary damage, and runearm charge and cooldown buffs, imbue increase and critical buffs.

Through enhancements and Epic destinies the build runs with 11 boosts of each type, these add Wis, Damage, and most importantly the GxB Endless Fusilade. With auto reloader, Blinding speed working the Endless Fusilade of the GxB will fire 26 times in the time it takes the 7 second animation to start and end. That is only one less than the 27 of the light repeater, but with vorpals on 19-20s.   

The Great Terror build is very Past Life dependent. You will need them for DCs, doubleshot, Hamp, Pos, HP, etc.. You will also need Epic past lives for both fate points and twists. You must also choose your active EPL & IPL stances wisely, it benefits greatly from +6 tomes but can be run with +5s.

Closely following the Class progression and Stat bonuses is important so that you are able to secure the full list of needed Feats at level with prerequisites. For instance you must start with Artificer to access Enchantment focus early, so as to free up slots later.

The GT can be run by other races but it will be at a loss to DPS and DC due to Wisdom bonuses and Feats. Over the weekend I did run and test a Deep Gnome version. Using DG you will have a 1 higher wis, +2 dodge, +4 MRR  but to acquire manyshot you end up taking more Ranger levels at the cost of 2d6sneak, damage to Xbows and 20% damage boost.



The Great Terror~
Human 12Rogue/4Ranger/4Artificer

Str  8
Dex 15 - +5 tome
con 14
Int 14
Wis 18 - +5 tome
Chr  8

All level-up bonuses to wisdom except for level 20 which is Dexterity, for Epic feats.

Level progression: 1Arty, 2-5Ranger, 6-16Rogue, 17-19Arty, 20Rogue.

Feats:
1)  Point-blank
1)  Enchant focus -human extra
1)  Proficiencies GxB,repeaters- Free Artificer feat
1)  Rapid Reload- Free Artifcer feat
3)  Completionist
3)  Rapid Shot- Free Ranger feat
5)  Precise Shot- Free Ranger feat
6)  Past life, Wizard
7)  Evasion
9)  Past life, Bard
9)  Uncanny dodge- Free Rogue feat
12) Greater Enchant focus
13) Improved Uncanny Dodge- Free Rogue feat
15) Many shot
15) Improved evasion, -Rogue bonus feat
16) Runearm use - Free Artificer feat
18) Improved precise shot
19) Improved Critical Ranged weapons - Free Artificer bonus feat
21) Combat archery
24) Embolden spell
26) Positive spell power
27) Blinding speed
28) Doubleshot
29) Elusive target
30) Epic sneak Attack (or Arcane insight if you need DC boost)
30) Scion of the Feywild


Enhancements:

http://i.imgur.com/Xvkijuh.png

NOTES: I avoid buying the Battle engineer damage boosts because currently the BE boosts are bugged so that they do not activate the Human Action surge that the build utilizes for +2 wis. If they are ever fixed I would purchase damage instead of runearm buffs. On the AA Tree, I occasionally trade Awareness for True strike.  Other than the Wis in AA moving over to action surge for 1, there is not a lot of room to move points around and still achieve the Build's purpose. Terror is the best bang for the buck currently as the non-vorpal scare effects everything it doesn't PK. No spell resist to AA arrow effects and the 3 second cool down on the Dispel shot means you can drop Mob deathwards constantly while getting another +4d8 damage.



http://i.imgur.com/TmPbVy0.png


Epic Destiny:
Exalted Angel or Legendary Dreadnaught (LD for heavy DPS Standing at cost of 6 DC)
Twists
-Enchant specialist
-Draconic pressence
-Pierce the Gloom
-3 extra action boost (LD, not shown in pic)
-Cocoon

Terror Arrow-DC Calculation:

1 Enchant focus
1 Great Enchant focus
1 Wizard PL
1 Bard PL
2 Embolden spell
4 Scion Feywild
1 AA terror
3 Exalted Angel
3 Enchant specialist
3 Draconic pressence
1 Profane DC
2 Enchant insightful
6 Enchant Competance
2 Enchant Greater Augment
1 Guild ship
______
32+20+30(wis)= 82 (88 with Arcane insight)

Yes, you could get higher with Bard song, lit, etc..  this is just where I am now and can maintain solo or in groups.



Final thoughts, I really liked the various builds that tried to use the changed AA imbues, but in every case I found that the procs didn't come anywhere near fast enough and the damage in between those procs or against red-names totally sucked to the point of making them useless overall. I tried many different variations before landing at the GT's fine balance of constant insta-kills and heavy boss dps. I have to admit that I was really surprised to find that in the end the build that could spit out the most procs per second was also the heaviest non-proc damage. I had tried bow, repeaters, and monk chucker builds and none of them could match the Proc rate, and only the chuckers came anywhere near the DPS.

Are you using longbows also? how you are using gbow with terror ?

Been away for a while, whats manyshot for? Thought it didnt work on xbows.

I assume you switch weapons. Also, you can retain an AA imbue on any ranged weapon by activating the imbue with a bow and switching weapons (at least, I think that's how it works. I haven't actually played any of these AA xbow/shuri builds).

Hmm, may have to try this out, if i can move around feats to not include manyshot, and go deep gnome, really want to play one

Also of note, if Manyshot is used 2nd during an attack chain the second Endless Fusilade can be started the moment Manyshot ends. The 1 second EF prep animation runs concurrently with the weapon switch, resulting in a quicker EF start as well.