"projectile" skill gem for bosses

Hi :)
I need any good "profjectile" skill (with support gems)

3BLUE 1GREEN 1RED

I use(manual) "Elemental Weakness" on bosses.
I have super increase ice spell dmg and just a little fire dmg
My skill tree:

I changed my post, maybe now its easier to give any answer :S

You could do ball lightning - lightning pen - echo - slower projectiles - life leech.

even if I havent "increase lighting dmg" build ?

Oh I didnt tell you abut my resist weakness, I dont need any penetrarion gems because I use(manual) "Elemental Weakness" on bosses.

So
ball lightning + echo + slower projectiles + life leech + concentrated effect ?

Here's a really quick passive tree swap I mocked up to work better with BL:



I just moved a couple points around and took out some of the really inefficient nodes and put more life in. You were only at 100% or so increased life which is way too low. You also skipped the power charges which are definitely a must for crit builds. You can use assassin's mark with herald of thunder to get charges. HoT is already a good thing to use with BL.

Honestly this is still a pretty inefficient tree IMO, but you won't need many refund points.

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seba11pl wrote:

Oh I didnt tell you abut my resist weakness, I dont need any penetrarion gems because I use(manual) "Elemental Weakness" on bosses.

So
ball lightning + echo + slower projectiles + life leech + concentrated effect ?

Bosses have reduced curse effectiveness and even if your enemies are at 0% res, penetration is flat out 37% MORE damage with no area penalty.

Penetration gems are simply unbeatable for elemental spells.

EDIT: Oh jeez I didn't realize your query was more specifically for single target. Are you using a staff or something for AOE?

My Gear:

Yesterday I changed gems in Atziri's Boots (elemental weakness and reduced mana) and today Portal -> Vaal Grace(armor)

Oh, so you aren't just looking for a supplementary single target skill. That being the case, all my advice is still relevant.

It's also worth mentioning that you ought to shoot for more life on your gear, and maybe swap the atziri belt out for a solid life/res belt. The meager amount of leech and damage on Dory's won't be very helpful if you link life leech to your main skill. And rare belts have a ton of potential life, which it looks like you really need.

There are three options for elemental projectiles to shoot at bosses: Ball Lightning, Arctic Breath, and Fireball. Ball Lightning is just a high-tier skill that does lots of damage, so no secret why that's on the list. Arctic Breath is more commonly seen in CoC builds because of the relatively high cast time and lowish damage, but makes bosses easy because of the chilled ground. Fireball is an unpopular pick, but with lots of elemental damage increases it can serve the same purpose for Spellcasters that Puncture serves for phys bowers.