I was looking at the Marathon SAR recently, and that inspired me to getting my hands on the military performance specification for wristwatches. You hear “MIL-SPEC” all the time, and see it advertised on some sites, but what does it actually say? Well, I’ll tell you.
The relevant regulation is MIL-PRF-46374G. I went through it to determine how close my Superocean is to being a MIL-SPEC watch. Below are the relevant sections pulled from the MIL-PRF. See if your watch meets military standards.
We will be looking at Type II and Type III, Class 4 watches: Mechanical, maintainable, anti-magnetic, water-resistant, high-altitude, and corrosion-resistant. Type III includes an elapsed time ring (diving bezel).
Case
- Silvery metallic or black color
- Non-specular/non-reflective finish
Dial
- Dial is black
- Arabic numerals 1 to 12
- Smaller Arabic numerals 13 to 24 concentric and inside of 1 to 12
- Numerals and indices are white
- Manufacturer symbols or name not to appear on dial
Movement
- Minimum 36-hour power reserve
- Minimum 15 jewels
Operation
- Pulling out the crown stops the movement and allows setting of the minute and hours hands without movement of the second hand
- The minute hand does not jump more than one hand width when the crown is pushed in
Bezel (for Type III)
- Background is the same color as the dial (black)
- Except for the 12 position, numerals shall be used adjacent to the hours
- Numbers and indices are white
- Minute marks at least from 12 to 4
- Periphery of the bezel is “checkered, knurled, serrated” or otherwise designed to facilitate turning
Accuracy
- 4.4 C ( 40 F): Mean daily rate of +/- 60 seconds
- 23.9 C (75 F) : Mean daily rate of +/- 30 seconds
- 51.7 C (125 F) : Mean daily rate of +/- 60 seconds
Lume
- After having been stored in complete darkness for eight hours, watch is readable in total darkness while holding it no closer to the user than 30.5cm (12”)
- Lume is visible without any action from user (such as pressing a button)
Durability
- Static pull of 15 +/- .5 pounds on the strap from each end
- Drop from height of 50cm (19.7”) onto 3mm thick vinyl tile on top of a cinder block
- Storage at -45 C (-50 F), 15.5 C to 32.2 C (60 to 90 F), 60 C (140 F), and 15.5 C to 32.2 C (60 to 90 F) for 24 hours each
- Complete immersion in water at one atmosphere, then three atmospheres for five minute each
- Subjected to 125 Gauss magnetic field for 10 minutes
- Altitude of 10,700m (35,000’) for an hour
- A solid sphere weighing 15.7 grams (.55 ounces) and 1.6cm (5/8”) freely dropped from 30.5cm (12”) onto the crystal
Other
- Strap is black
- Crystal recessed from bezel
My Superocean fails the non-reflective finish requirement. I’m not sure any Breitlings meet the bezel standard, being black with white markers. The requirement for minute markers from 12 to 4 also kicks out a great number of diver's watches that only go to 15 minutes. I also don't think there are any Breitlings which don't say "Breiting" on them, therefore failing the requirement of not having any logos or manufacturer text on the dieal.
All of our watches should handily exceed the accuracy requirements, however. The standard for quartz watches at the high and low temperatures is only +/- 3 seconds, which is achievable for a well-tuned mechanical.
