Ok a few fluff/basic usage questions

1. A pf creats a disruption field around itself right? This field distorts and renders useless armor and steel plates thus explaining its effectiveness. My question is why would the strength of the field depend on how strong the wielder is? Shouldnt a Guardsmen with a PF be just as effective hitting power wise as a marine? I guess one could debate they are petty quality PFs...

2. A terminator wields a Storm Bolter in one hand like a Marine would hold a pistol by a handle correct? The BT codex shows a great side pic of this in action (dont have the codex on hand so cant say PG #). Therefore why would a terminator not be able to bash in the side of a enemies head with it like a Sm does with a pistol? Should not a storm bolter be counted as a one-handed weapon in CC (Kinda like a kai gun becomes one-handed for a Daemon Prince) I have never heard of a Terminator needing to fire a storm bolter with both hands???

3. A GK terminator's storm bolter is actually mounted on its wrist completely leaving the hand open, prusmably to better wield his halbard. So them out of all should not count SB as 2 handed.

4. A GK in power armour uses its storm bolter also simi mounted on its wrist which can be seen on pg. 6 of the DH codex. The model shows a bracing bar that the GK uses to steady the SB in his hand (which probably includes the trigger assembly), while Pg 9 of the codex shows the SB completely back farther on his wrist not connected to his arm at all like the Termies use it My question is does this bracing bar really exist or not and if so how does a GK wield his halbard properly? A halbard is a rather long weapon and using it one hadned would be extremely hard, and the GK books talk about the Knights using thier halbards with both hands as logic would suggest. If the bar does it exist how do the Knights accomadate for it to properly wield thier halbards. I am thinking maybe the bolter draws back into a stored position.