Just wondering:

The description in the Rulebook for the "Heavy Blaster Pistol" states that it consumes ammo more rapidly then other guns and then goes on that therefore the GM can spend a despair to cause them to run out of ammo.

However, if I am not mistaken, he can do that for any weapon anyway.

In the beta rulebook it's "3 Threat or 1 Despair" … so is the 3 Threat just missing due to a typo or due to a simplification for the beginners ruleset?

I find this a bit confusing, because even in the Beginner Game Rulebook, it states on table 2-2 that the GM can spend 1 Despair in combat to cause the character's ranged weapon run out of ammo and be unusable for the rest of the combat. It doesn't limit it to just the heavy blaster pistol, so it might be that the game wants to emphasise that you should be more likely to choose this with the heavy blaster pistol than with other weapons.

I agree with sinosaur, it is a reccomendation that you use despair for a power cell running out for a heavy blaster pistol more often than for other weapons.