Did Canadian built Lancaster's have .50 cal. dorsal turret guns? I thought I saw reasonable replicas of the .50 cal. in the dorsal turret of the one that flew down from Canada a few years back, though the nose and tail looked as if the had Lewis's.
Yep, .50 cal Martin dorsal turret. Nose and tail turrets had .303 Browning guns (2 in the nose, 4 in the tail), with the later tail turret mounting twin .50 Cal Brownings.