Well according to that video the SMG also has a scope, and we all already know that it's not that powerful single wielded...

Thats not the SMG from h2 and 3.. Its a new type of silenced SMG but not the same SMG. I believe there was a thread about this awhile ago. And im gonna have to go with bigsick. They probably will be more powerful since they have scopes because if you havent notice all the power weapons have scopes............ besides the sword and hammer

It has also been confirmed that Halo: Reach is a FPS and if it follows the book series, this game will take place before halo:ce. In hindsight halo reach will feature the old school pistol.

Looks like I'll have to wait till 2010

Or not: M6C Magnum Sidearm - Halopedia, the Halo Wiki - Halo, Halo 2, Halo 3, and more

Scroll to where it says Halo 3: ODST. That's the Magnum from H2 but with a scope and elongated barrel. The damage has to be the same, considering it's the same gun just with those two slight differences.

Their source is a picture render of the new pistol, not very reliable in my book. We'll just have to wait till Sept. 22.

Ok, well how about this source? From Bungie.net...

Bungie.net : Halo 3 ODST

Go to Field Guide and then Ordnance...