I know that last tour (MW) I had several encounters against 3 ship formations of Lancs, while upped in a Yak9T. Typically would hit at least one bomber with 6 rounds of 37mm and see parts fall off........the kill was the exception for me dealing with Lancs. The Yak9T had great success against fighters, for me at least.
Last night I encountered a 3 ship formation of Lancs while upped in a P39D. I killed all three bombers and still had 11 rounds of 37mm left.