8,8 cm PzGr
Rich, Marty,
Rich you are quite right, except for cavity size.
The 8,8 cm PzGr 39 and 39/1, to my knowledge, had the same cavity size.
However, the earlier 8,8 cm PzGr (no additions to this nomenclature!) had a larger cavity size and used a different Zdr, the BdZ fr 8,8 cm PzGr (a notably different design) instead of the BdZ 5127 used on the 39, 39/1 and 39/43 types.
KwK 43 and PaK 43 indeed fired 39, 39/1 and naturally the 39/43, the latter having wider drivingbands. The 39 and 39/1 could only be fired as long as these guns hadn't yet fired 500 rounds. The wider drivingbands on the 39/43 were meant to deal with both loss of pressure and somewhat correcting the effects of wear in the barrel.
The FlaK 41 used either 39 or 39/1, the earlier 8,8 cm PzGr not being designed to cope with the higher pressure generated by the lager propellant charge in the longer "41" case. I have no info on FlaK 41 firing 39/43 but have never heard his mentioned (and it seems unlikely).
Flak 18/36/37 fired 8,8 cm PzGr, 39 and 39/1
greetz,
Menno.