An interesting point I have not thought of so far. I can only recall the rules saying that the combination of a Gun+Crew are considered one squad-equivalent. Where can you find that the Guns by themselves to not count at all?
Would this theoretically allow to stack a bunch of Guns in a Pillbox setting up HIP unpossessed and thus to potentially break a scenario in which the VC require to find those Guns?
1) COWTRA. The crew/hs possessing a gun is listed under D5. A gun or multiple guns by themselves without reference to a possessing unit isn't. Per A4.43 a unit can possess any number of guns/sw, but that doesn't discuss stacking.
As an aside, a gun possessed by a SMC (presumably heroic or with another SMC present to help fire it) counts as the possessing SMC(s) for stacking, and of course an unpossessed gun counts for nothing.
2) It's not clear to me how the rules interact here. A pillbox & its contents sets up HIP, but an unpossessed sw/gun can't be concealed. My guess is that the unpossessed guns are put on board but the pillbox not. Perhaps someone who cares about this will send in for a q&a.
In PTO this might be a problem perhaps if the pillbox can create HIP for unpossessed equipment. In non-PTO the pillbox itself will lose concealment on LOS w/i 16 hexes, and it is highly likely that someone would poke his nose in it. But the pillbox is an unnecessary frill for any potential breaking. Just HIP the guns possessed by a crew anywhere. No need for a pillbox. But then if it's necessary to find all the guns, why put all your eggs in one basket? HIP them all over the place. Of course if the VC are to find any one gun HIP-ing them all in one hex might be better.
edit--as Klas has it, having multiple guns in one pillbox is not only unnecessary but actually violates a rule. The pillbox is still unnecessary to break the scenario unless you need every last MMC fighting because otherwise one crew possessing all the guns will break the scenario too.
JR