I use to think that was the case. The first cracked frame Flues I saw was a 28-gauge in a shop in Fredericksburg, Virginia, probably a good four decades ago. But, a few years ago I scored a packet of 1932-33 letters between a customer in Cumberland, Maryland, and Ithaca Gun Co. concerning a cracked frame 10-gauge No. 4 that was purchased in 1921, and according to the customer had only fired maybe 75 to 80 cartridges in the ensuing eleven years.