I have only owned one of these little Cadets. I would not think that you could chamber a 32-40 due to the length of the case. As I recall they were very short actions. Don't know for sure. Can you get the original 30 cal. brass for these rifles? I know back in the 1960s they sold as new for around $15.00 and there was no ammo. Most were reamed to 32WCF with a drill bit.