I'm just starting to load for the 38/40 WCF and I have a lot of old Winchester loaded ammo. The ones that were loaded with jacketed bullets  I shot for the brass but those with cast bullets were loaded with BP so I pulled the bullets and dumped the powder. The newer cases take a large pistol primer while the BP cases take a small pistol primer. We've all heard of the infamous Balloon Head cases but I wouldn't know one if it bit me. The question is should I try to use the BP cases or should I avoid them altogether?  Thanks