Ok, but the "single attack" does mean a semi or a full auto burst, yes? I think I've read about it somewhere on these forums. Could be wrong though.
Where's the source on a single shot only in melee? I've read both the rulebook and the errata and couldn't find it.
No, it means a single shot.
The ruling on single-shots only in melee came from a rules answer from Ross Watson in 2011 (before BC and OW were released, so he does not specify those games in his answers, though it is safe to say the rulings apply to all the game lines).
See post #19 in this thread. I quote, for your convenience:
"> 1) Can pistols burst in close combat in DW? (And if yes, doesn't
> that carry a high risk of wildly straying shots?)
No. Pistols fired in melee fire a single shot.
> 2) If no, does that mean this is a DW-specific change or does that
> apply to all of 40k RP?
It applies to Dark Heresy, Rogue Trader, and Deathwatch.
> 3) What actions can be done with pistols in close combat other than
> Standard Attacks? Multiple Attack (if so only 2-handed attacks only
> or does swift strike, etc also apply)? All-out attack? Guarded
> attack? I am asking because page 240 indicates more than standard
> attacks are possible.
Standard Attack (or as part of two-weapon fighting) only.
> 4) Does the answer given to question 3 carry on to all of 40K RP or
> only DW?
It applies to Dark Heresy, Rogue Trader, and Deathwatch."