In this video
you can see at 1:23-1:26 where is says 8/15 unlocked. It is obvious this is referring to Primary weapons because it shows the assault rifle, and that is the Primary weapon slot. This thread was made to speculate what those 18 weapons are. 343i stated that the primary weapons will be strong, but not OP ex; Sniper, Rocket. The most likely and strongly hinted at by players to be loadout primary weapons are:Assault Rifle
I will have the confirmed weapons in blue and the speculated weapons in red. We will speculate and decide on the most likely ones. I will guess the Light Rifle, Scattershot, Plasma rifle and/or repeater, Forerunner repeater, (confirmed in blog) and that is it so far. What do you guys think?