I'm afraid to report this one, I might jinx myself.
Germans are assaulting me outside of Leningrad now, with multiple regiments of off board 105mm and 15cm guns. Apparantly the Kapitan of my counter-battery unit is taking this personally, because he has fired 5 CB missions in the first 12 turns of the game. He's not just lobbing a few shells, either, most of his missions are landing 14 or more hits with his 152's.

At this rate, I'm worried about his ammo state, just from CB fire.
It's not slowing down the Germans much so far, but if he keeps rolling 20's and pounding them, it may make a difference yet.
Matt