What does 'tec5 296 AAA slt bn cac' mean on a tombstone?

Answer 1

Tech 5 was the rank of the deceased when in the service. It was the same as a corporal, but for men in technical specialties, such as radiomen, mechanics, and so on. The badge of rank was two chevrons, like a corporal, but with a large capital "T" below to indicate Tech 5, not corporal. The person holding this rank was usually addressed as "corporal", though.

The rest is 296th Anti-Aircraft Artillery Battalion (Searchlight), Coast Artillery Corps. This was a unit whose job it was to try to pick up enemy bombers at night with huge searchlights, and hold the light on them so the anti-aircraft cannon could shoot them down. Such a unit would have had a fair number of technical specialists.

The WWII Army had a large number of "independent" battalions, such as this one. They were independent because they were not a permanent part of any larger formation. This was so they could be moved around and used when and where they were needed. Unfortunately, this means it is often hard to track down information on the independent battalions, especially when compared to the wealth of information available on all the US WWII divisions, which were much larger. A battalion such as this one probably had around 700 men, total. Some have reunion associations, "alumni groups", but I did a quick web search and did not find any for this unit. If you wanted to try searching you might search for "296th AAA Searchlight Battalion".

I did find a webpage about a sister battalion, the 225th AAA Searchlight Battalion, with lots of pictures. This would be very similar tot he 296th. See the related link below.