ok 1st off it only hits the ones in line which means it cant be randomized in the shot......give me 5 min to dig it up and Ill edit this to have the exact wording(fun) which is pretty legnthy.
the answer is right in the rule(missed it till I typed it up that part is in bold) I did not add anything to the rule except maybe a miss spell here and there
ok so from the fireing the cannon part of its rule(yes all of that part):The warp lightning cannon is a move-or-fire weapon like all other war machines.
To fire the cannon, first point it in the direction you wish to fire. Note that the special warstone-powered aiming sight allows the skryre adept to see through terrain and troops, so you don't need a clear line of sight to the target. The cannon can be fire in any diffection, even though your own troops- no restricion applies whtsoever. for convenience, it's better if you indicate a model as a target and line up the barrel towards it.
When the machine is fired, a bolt of leathal warpstone is released in a straight line from the cannon's muzzle. Roll 8D6 and total the score to determine what the range in inches the lighning proected from the gun is going to be that turn.
Determine which models are hit in the way as you would do for the bounce of a cannon ball, except that all models (friend and foes) lying along the entire line's length are hit. There is no need to randomise hits if the line goes through models engaged in close combat with the enemy, all the models lying under the line are hit as simple as that (note that this is an exception to the normal rules for shooting in close combat)
Roll an artillery dice. models hit by ligtnigh suffer an automatic hit at the strength rolled by the artillery dice. Armour saveing throws as normal, modified by the strngth of the cannon.
If you roll a misfire refer to misfire chart on the right.
ok so like I said that day only hit the units in the line
yea sorry I missed that part....its pointed out right in its own rules not sure how I missed it, oh well answers the question at least