Pocket Watch or Stopwatch ID?

[jbart]

A friend came across this watch and we're interested to learn any known details. A specific use and date would be great.

Here's what we think we know:
the M stands for Navy
the Artl is for artillery

And that it has "60" makes me think it's more of a stopwatch than pocket watch

[bigmacglenn]

Junghans-produced Navy/Coastal Artillery-Marked Stopwatch...It's obviously not a pocket-watch as it doesn't tell the time...These are definitely desirable and I see them sell for several hundred dollars...
cheers,Glenn

[Wagriff]

These were used more as shell timers than anything else. Crucial business to know when firing heavy artillery. Very collectable and nice to see one well marked. Is it working?

[harryamb2]

a nice collectable item.