help identify marks on silver pocket watch???

I have recently inherited a sliver hallmarked pocket watch. All I know is that it was my grandads and he used it whilst being in a the army and fighting in the war.

It has one stamp, that I think is the swiss marking (grouse)
It is marked warranted 0,800 silver with the letters A C and the number 30171. There are some tiny engravings of other numbers that seem to have been etched in.
One of them looks like 29/5/16 and C86 H90 and 30619h3.

Hope this descrition helps…it wouldnt let me upload my photo, syaing the file is too large!!
Hope to hear from you soon