The 6 pounder is a gun, the RP-3 (3inch diameter) rocket is sometimes called a 60ib rocket (explosive) or 25ib rocket (armour piercing).Im not so sure about rockets being effective against aircraft/bomber formations. Didnt the Luftwaffe try that on US day bomber sorties? From what i've read it wasn't all that successful or even practical. A bit haphazard with mixed results. Not to mention aircraft loaded up with rockets and heavy canon were meat on the table for escorting fighters.