Most Defensive Primary

No, I did not typo that.

Among the scrapper primaries, IE, attack sets, which one gives the most mitigation?

Dark melee is pretty obvious due to siphon life, but how about martial arts and the stuns+knockdown? Weak sauce?

Is there another primary that's better for survivin'?

Reasoning: I'm looking at a build designed for no exemping which uses the fire APP as most of the attack chain, and want to get some mitigation from primary powers to complement the secondary and incarnate powers.

Thoughts appreciated!

invul, period, no questions asked

Don't forget that DM also stacks -acc and has touch of fear. I don't know if it competes with the swords, but it's got to be top 3.

My level 50 Dark Melee/Invulnerable Scrapper is one of my favorite toons. Dark melee lowers their acc and I have near tank-like defences (even better than some tanks I've run with.)

Out of the Box DM, Kat, and BS are the easy winners.

If you are looking at end game, spines could be made defensive with the Diamagnetic interface. 5% to hit off of every tic from quills capping out at 25% which is essentially half way to soft cap through debuffs.

Additionally removing most of the incoming damage (From Minions) quickly and then slowing bosses so you can easily kite them with the occasional KD in ripper makes it... sort of defensive. Still no where near the first three though.

Katana and Broadsword have Parry. It is going to be hard to beat that for any primary, even if they did not also have some knock in their last two attacks.

Dark Melee might be a distant third, depending on your secondary. Siphon Life is a solid heal without diminishing damage output, and the to-hit debuffs on every attack are solid against any single target under an AV.

I rank them like this:

1) Katana or Broad Sword for no or low defense secondaries
2) Dark Melee for no healing secondaries
3) everything else