In the 1970's Hamilton produced field watches under the Mil-W-46374A & B specs and also aviator watches under the GG-W-113 spec. The Mil-W-46374 watches had 7 jeweled movements and were meant to be disposable. Their accuracy requirement was +/- 60 seconds per day. The GG-W-113 watches had higher quality 17 jewel movements that were more accurate and meant to be serviceable. The GG-W-113 was twice as accurate and required to meet +/- 30 seconds per day.
I recently did a post on a Hamilton model called the W-10 that was produced for the British military. It's also a high quality watch with the same movement that was used in the GG-W-113 watches, the Hamilton 649.
In 1986 the US military changed the specs for field watches and issued the Mil-W-46374D update. The specs included five different types. Types 1 and 2 had mechanical movements and types 3, 4 and 5 had quartz movements. Type 1 models required a minimum of 15 jewels and improved accuracy of +/-30 second per day (at 75 degrees F). Type 2 specs were more relaxed with no specific movement requirements and accuracy at the previous standard of +/- 60 seconds per day.
Hamilton produced Mil-W-46374D Type 1 models.
To be completely honest, the earlier Mil-W-46374 models aren't very interesting or appealing to me. They're nothing to brag about... 7 jeweled movements with accuracy far less than anything else bearing the Hamilton name. The GG-W-113 is a far superior option, if you're looking for a field watch.
That said, I've had my eye out for a Mil-W-46374D for quite a while and for several reasons. They're considerably less common than the earlier 46374B models and they typically sell for "good money" - meaning upwards of $400 - $500.
First off, the Hamilton Mil-W-46374D has an excellent movement, the ETA 2801-2. So it's as good, or better, than the 649 movement in the GG-W-113. Second, having worked recently on the 649 movement, I was a bit curious if the form and fit of the 2801-2 and the 649 were the same. Could a 2801/2 replace an ETA 2750, if necessary?
As fate would have it, I recently landed a Mil-W-46374D that was in need of a little TLC. As received, the only thing wrong with it is the crystal is cracked.
The case for the watch is a two-piece design. The spring bars are fixed and not removable. The case back is stamped with a variety of information, including a unique serial number.
There are no hole on either side of the case for the spring bars. The crown and the case are "parkerized", a special coating used to inhibit corrosion.
The inside of the case back is marked with Hamilton and made in Hong Kong.
The movement looks very similar to the 649. That's not too surprising - all ETA movements share a lot of similarities.
You can tell that this watch was made in the 1980s... West Germany no longer exists.
The dial-side of the 2801-2 is different from the 649. The 2801-2 can also have a calendar complication. Although this version is missing all of those extra parts, you can see where most of the calendar parts would go.
With all the bridges removed from the back, you can see the full wheel train. You can also see the L-shaped lever used to "hack" or stop the watch when you pull the crown out to set the time.
The waterproof crystal has a matte-finished reflector ring. The crystal is cracked and will need to be replaced. 28.5mm will do the trick.
Here you can see a 649 movement, based on the ETA 2750. Although it's similar, it is not identical to the 2801-2. The movement feet are close but not in identical positions so the dial from a GG-W-113 will not fit on the Mil-W-2674D, and vice versa.
Everything is cleaned and dried before being reassembled with fresh lubricants.
The only difficult thing about reinstalling the hack lever is to remember to do it. Most of the time I get the watch back together and then I realize that I forgot the lever and have to take it apart again.
The movement is now reassembled and ticking away with good motion. In fact, the beat rate on the 2801-2 is 28,800 beats per hour - way faster than the 649 movement. So the ticking is noticeably faster than most watches I work on. Ordinarily I would be very concerned if the watch was ticking this fast but for this model it's a good sign.
Well... not too bad... a little fast and the beat error is 1.0ms. I can correct both of those attributes with just a little tweaking.
There... 16 seconds fast per day and a beat error that is right on the money. I suspect the beat rate will level out after a little while.
Since the bars on the case cannot be removed, the best strap option for a watch like this is a Nato-style strap. These one-piece straps come in different colors and the colors are meant to replicate regimental colors, although black or olive is a great choice too.
This watch looks a good as it runs now and will be a great option for casual wear.
Now, if you think the Mil-W-46374D is something you'd be interested in getting, you should check out the new Hamilton Khaki Field that Hamilton recently released. This new model features the exact same movement - the 2801-2. Hamilton will tell you that it's inspired by their 1940's military models - and maybe that's true - but it sure looks like a Mil-W-46374D to me. However, it's actually a bit larger. The new model is 38mm wide (excluding the crown) compared with 34mm for the vintage model. The strap on the new Khaki Field is 20mm wide, vs 18mm on the older model.
Still, I like the looks of the new Khaki Field and with a sapphire crystal, instead of plastic, it's probably a bit more durable too.
Just to put it in perspective, here's a family portrait of the W-10, GG-W-113, and Mil-W-46374D side by side. Looking at it this way, I'd say the new Khaki Field is modeled on the GG-W-113. What do you think?