Congratulations, 'Nando,
I just wanted to point out this link as your grenade doubtlessly is one of the Thirty Years War pieces dug up in Ingolstadt/Bavaria in the 1970's:
http://www.vikingsword.com/vb/showth...des+ingolstadt
In my glass case, 2nd image from top, on the right hand you can see two original fuses, one of them cut in half to show the powder line inside.
Best,
Michl