....to admit that what I thought was A.C. (Armored Car) No. 1, painted on the left side of the T4 armored car shown in the second photo down in my previous posting, turns out to be A.C. No. 7. The right side view of this same AFV appears below.
If that numbering sequence is unique to the T4 and M1 armored cars, then I need to modify my belief in the number of such armored cars built; if that sequence is unique to the T4 cars only, then I need to modify my belief even moreso. If, however, No. 7 is simply that in the general sequence of armored cars being tested by the U.S. Army in the early 1930s, then I may not need to modify my original hypothesis. The American army looked at several different types of armored cars during the interwar period, most of them built in ones and twos on readily available commercial truck chassis and armor-plated at Fort Holabird in Maryland. Here are just two of them, the T8 armored car (Chevrolet chassis) of the late 1920s-1930 and the T6 armored car (Franklin chassis, evolved from the earlier T7 armored car) of the early 1930s.
For the numerous armored cars tested by the U.S. Army and their development chronology (the cardinal numbers assigned to these wheeled AFVs do not
follow along in a nice sequence), see
However this shakes out, we need to be receptive to the alternatives until production numbers of the T4 and M1 armored cars are clarified.