A number of nations purchased and issued broomhandles on a limited basis. German "red nines" and Persia have been mentioned. The Russian Red Army bought and issued many short-barreled "bolo" Mausers, the Italian Navy issued "slab-side" versions, the armed SS issued full auto types, and the largest user doubtless was China, which purchased thousands of C96s, Spanish Astra copies, and produced more-or-less crude replicas, including one model in .45 ACP calibre.
I participated in the first wave of Chinese broomhandles imported into this country in the 1980s, all allegedly legal as they were certifed as having been police issue. Opening each crate was an adventure. ALL the above types were represented, including one Chinese copy of the sort fabricated on a flat rock: it was stamped "Wauser".
To use a C96 in CAS, wouldn't one have to hand load lead bullets?