Can someone tell me which sheild is best for gunner (piercing) ?
Sheild for gunner ?
The standard practice is to keep shields that protect you from each of the types. Since smart gunners usually hang back they can get away with keeping lower star shields than their sword or bomb toting counterparts because in general the gunner has much more time to react to monsters attacks (since the monsters are further away).
Gunners that are more confident in their dodging abilities will bring a swiftstrike buckler to take advantage of it's weapon attack speed boost.
Aegis is only good if you're lazy and do not want to spend time getting a much better Shield. It doesn't provide any Status-Immunity and the base stats are actually really low and can be easily compared to other shields.
The best piercing shields are Royal Jelly Shield / Savage Tortoise (Latter is better if you have the Ancient Shells to get it or do not mind the Movement Speed Decrease), Dragon Scale Shield, or Ironmight Plate Shield.
Depending on your preference and difficulty setting, Dragon Scale Shield might end up being the better choice out of all of them: All Beasts inflict pure-piercing damage on Elite to the Shield where-as I'm almost certain all Slimes do too.
To get many more opinions quickly, try this Google search:
gunner shield site:forums.spiralknights.com
The short answer is just to get Swiftstrike Buckler, until you are farther along in the game and have stronger opinions. Happy travels.
Swiftstrike is good because it gives a massive boost to your attack speed. It has pitiful defenses, but if you're gunning, you won't miss out on much until much later; oftentimes you'll be out of range of enemy attacks, or have enough distance that you can dodge anything that gets thrown at you. One of the biggest things to keep in mind about the Swiftstrike Buckler is that it can't be crafted into anything else.
If you want a more defense-inclined shield that lets you make more mistakes and also stays effective in T3, you should pick up an Owlite Shield. It doesn't give piercing defenses, but has two huge status resistances to Fire and Shock, two very dangerous status effects. By the end of the game, Elemental and Shadow defense is more important than Piercing defense.
If you absolutely need piercing defense ASAP, don't go with the Defender series. You should use the Jelly Shields, which have a little less normal defense but more piercing defense and HP, with a nice resistance to Stun as well.
Also, for clarity- shield status resistances don't affect the intensity of the status if it hits you, but it lets the shield tank hits that deal those statuses more easily. Statuses deal 'extra' damage to your shield.
I haven't really had any issues with the lack of status resist on my Aegis, especially when I'm gunning. Since gunners are usually farther away from the main bulk of the fighting and given the slow travel speed of most enemy projectiles, I don't take much fire and can easily evade what little fire I do take.
I personally don't use swiftstrike, because the build I use gives me Max ASI on its own, provided I use the right sprite perk. Depending on what 5* gunslinger set you're using, you might not want to use it either.
Aegis carries a nice amount of normal and piercing defense. But piercing defense is arguably the least important damage defense in the game. And tests of shields suggest that status protections are more important than damage protections. So Aegis ends up being one of the worst shields in the game. Does that mean that it is unusable for a gunner? No, it's usable. But why invest your crowns, fire crystals, etc. into this weak shield?
I'd even recommend Barbarous Thorn Shield over Aegis. For gunners the two are roughly equivalent, and you might use swords some day.
If your build gives you ASI+6 elsewhere, that's great. But you don't have all of your other stats (CTR, damage bonus, MSI) maxed out. Using Swiftstrike for ASI opens up more of your armor, perk, and trinkets to work on these other stats.
My first set ever was built around gunning, til now my only usable shields are swiftstrike and crest of almire(really used to just get passed HoH). And I do agree with Bopp, status resistant shields seem to protect more, want proof mail me in-game and ill show you my buckler with stun resistance high negate most if not all damage from a trojan in Tier 3.
Honestly, Aegis would be fine if you need a piercing shield. You won't be taking hits often enough that you'll need a lot of shield health as a gunner. Dragon Scale can also be handy, since its piercing/elemental protection will block most ranged attacks.