Some other details.....On the officer helmet you can see a mixture of brass bits along with the zinc and this is typical for these wartime models. For example the pearl ring around the neck of the spike seems to be brass, the stars look to be brass and there are a couple of scales that have either retained their "wash" or are actually brass. The chin scale bosses at the sides of the helmet seem to be brass as well. So, a mixture of brass and zinc parts. They turned to zinc manufacture due to a brass shortage during the war. Brass was needed for shell casings so again, as in WW2....zinc pot metal.
Regarding the M15....it's grey fittings also reflect the brass shortage as well as providing a less shiny helmet. The markings BA XVIII represent the Army Korps to which this Regiment belonged. Germany was divided up into Army Korps districts with different Infantry, Cav and Arty regiments stationed within. I can not read the Regiment stamping. All Korps markings are usually stamped in Roman numerals although some like the XVIII sometimes use "18" to save space. Regimental numbers use our normal Arabic numbers.
