Archon + Fire dragons bomb

I'm new to posting in the tactica section but I would love to hear what people think about this and to clear up some quite complicated rules issues.

Note1: [I also may have totally missed something in the rules that prevents me from combining these units so apologies in advance if this is the case.]


The Combination:

110 - Archon , Blast Pistol, webway portal
Blaster: 18", str8, ap2, Lance, Assault 1
Webway: "If a model with a webway portal is in Reserves or Ongoing Reserves, then the model and any unit it has joined or is embarked upon has the Deep Strike special rule. This model, and his unit, will not scatter if arriving from Deep Strike Reserve."

132 - 6 Fire Dragons
Melta gun: 12", str8 , ap1 , assault 1, melta

Total: 242

Against an AV12 imperial knight with no saves these 7 models will inflict 6.652777778 hull points

I'd also take an autarch to modify the reserve rolls.
Thoughts?
I prefer this to trucking my fire dragons up the board and getting shot to sh** before I make it to the enemy.