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

The .44-40 cases I have for Small primers are semi-balloon head and I use them exclusively with black powder and cast bullets.

The rims are solid but the bases are otherwise thin (about as thick as the rim, only slightly thicker than the sides of the shell) and the primer pocket protrudes into the case.  A true balloon-head shell I've frankly never seen, at least empty in any reloadable quantity; it would have the rim folded over and the base only as thick as the rest of the shell, like a .22 rimfire and the primer pocket the same thickness, protruding into the shell like the semi-balloon head pocket does.  I can't imagine that even with black powder, they were good for more than a reload or two before failing somewhere.

I generally lose a few cases every time I load my dwindling batch up, typically from neck splits but also from the primer pocket swelling or (rarely) the end blowing away into the shell and down the barrel.  It doesn't allow any blowback with black powder and my Low Wall seems to be able to stand the gaff, but there are fewer and fewer cases to reload every time I shoot them up and clean them.

I fully realize that this is an idle exercise and probably not the wisest course for a reloader, but I like to see what the ODGs had to put up with, so I do stuff like this.

I was under the impression that any case that had a raised primer pocket when looking inside the case was a balloon head case.