We have several 7AM's w/ the sweep second complication on site. Dr Ranfft doesn't list the 7AM, but he has several 7's listed on his site. Most of those which are "close" to 7AM have a sub second, which can pretty easily be modified to be a sweep second and for what ever reason, the "C" part of the 7AMC wasn't stamped on the bridge for some of these perhaps earlier movements w/ sweep second.
Here's Jab's 1943 17 jewel example from this 1944 American Nurse record.
We also have a 1946 7AM w/ sweep, from this "non-conforming" record, so maybe it wasn't just the older movements which didn't have the "C" part stamped on bridge.
I'm faced with a bit of a conundrum. According to all accounts this was the movement in the early '40s Nightingale, which prominently advertises a center sweep second hand, but if this movement didn't have one, then what's going on with the examples on this site and Watchophilia?
We probably got something slightly wrong over the years. I'll check it out. Agreed that models advertised with sweep second hands should have a movement w/ that complication, if you will.
7.75''', based on ebauche AS 1001. The 7AMC had the sweep second hand.
Was this movement only used in ladie's watches?
Does this movement have a center seconds hand?
1945 - 17 Jewels
I've got 3 ladies model Bulovas with 7AM movements and none of them have a seconds hand.