Dwight,
It's most likely a German signal/flare gun. They used them quite a lot at the front.
Also included a picture of a German soldier posing in 'wild west' style. Purchased this one a while back:
<a href="http://forums.lugerforum.com/lfupload/duitser_01.jpg" target="_fullview"><img src="http://forums.lugerforum.com/lfupload/duitser_01.jpg" width="400" alt="Click for fullsize image" /></a>