Hello Ken, welcome to myBulova, thanks for sharing the heirloom watch you found. This is a man's watch produced for the US military in the 1950's and early 1960's. The earliest one we have in our dB is dated 1950 the latest one 1961. Bulova, along with several other watch companies produced watches for the US government under several specifications, this one being Spec MIL-6433A and was classified, as you can see, as a navigation watch. While the market is flush with these watches (think of how many men served in the US armed forces over that period) the ones that can be attributed to a family member (father, uncle etc) can be special family heirlooms. I hope you can tie this one to a close relative. To properly assign a a year of manufacture it would be nice to see a crisp photo of the movement but if you can't get it to a jeweler to open it we would probably pick a late 1950's year to date it. If you choose to get it serviced and cleaned up we might recommend someone depending on where you live. I would not do anything but service it and have it gently cleaned. A nice black or brown leather strap would be a perfect fit.
We will classify your watch as a 195X Bulova Military Issued A-17A