Is this just Blaster with pierce or is there a new mechanic?

Yes to having a new pierce gun, maybe to using the standard (Proto, Blaster) mechanic; then again Blaster is the only upgrade line using standard in terms of gun mechanic.

The nailer... thats an interesting name. :3

The name is really wrong.

If you know what i mean

I'd love that

The name sounds like a sex toy. What were you thinking?
@Diamondshreddie while we're on the topic... hole puncher? Really?

I believe this thread deserves a good, hard bump.

No. It's pretty much a blaster and a Magnus. And what you showed for damage had no normal damage at all. Your saying it has normal damage with it, when you didn't even look at the stats you posted. Plus what is the point of another piercing gun? There is enough already. Almirian and heater shield still have normal damage, so really u failed to prove your point.

"No. It's pretty much a blaster and a Magnus"

Well DUH, it's supposed to be pretty much a blaster, seeing as it comes off that line. And how is it anything like a Magnus, apart from the damage type? What, do you have a problem with the Cold Iron Vanquisher, seeing as it's pretty much a Leviathan Blade with an undead bonus, and the Irontech/Deconstructor/Big Angry Bomb, which are pretty much Nitronomes?
Why can't weapons be similar to other weapons?

"Your saying it has normal damage with it"

No he didn't, he didn't say that anywhere.

"Plus what is the point of another piercing gun? There is enough already"

You've failed to see the point, have you ever been a gunner? There is only the Blitz and the Magnus. How is that "Enough piercing guns", it's only two. Not to mention both of those guns you must stand still in order to fire, while all other damage type guns (3 normal excluding Slug and Pepperbox, 3 shadow, and 3 elemental) allow you to move while firing

"Almirian and heater shield still have normal damage, so really u failed to prove your point."

Nope, he proved his point just fine.

Firstly, Almirian and Heater shield are armors and shields, which are different, mechanics-wise, to weapons.

Secondly, Almirians special defense changes from piercing to shadow, and Heater Shields special defense changes from piercing to elemental, both obtaining stat resistance alterations.
The one thing that stays the same is the Base defense, which is normal.
Blaster's damage type will change from normal to piercing
The one thing that stays the same is the style of attack, which is a three shot with movement speed reduction
See the similarities between the branchoffs?

I can prove this logic is correct because you can carry it across to other equipment lines.
Magic line goes from Normal/Elemental to Shadow/Elemental with the Divine branch, while retaining the original elemental defense and stat resist, also gains an offensive bonus and a new stat resist
Autogun line goes from Normal to Piercing while retaining the original attack style, and also may gain a new stat, depending on which line it takes.

Plate line goes from Normal/Piercing to Normal/Elemental with the Volcanic branch, while retaining the original normal defense, ASD penalty and stun resist, while gaining a new status resist.
Troika line goes from stun causing to freeze causing with the Triglav branch, while retaining the original attack style and damage.

One add-on thing is always traded off while the core of the equipment is kept.
In the case of Armor, it's usually a set purpose like status resist, perhaps a certain defense, or an offensive bonus.
In the case of Weapons, it's usually the attack and charge style of the weapon that stays the same, while the type, status and damage are free to change.

Thirdly, only melee weapons deal split normal damage. Spiral Knights physics states that projectiles will always deal pure damage of their type, while bombs are a little wishy-washy because of how they operate.