What exactly do you mean by conventional ball ammo? Handloads using Paradox bullets? Spherical Balls?
Paradox style bullets are what you want to be running through this gun, or if you can find a source for LT caps somehow.
If you don't want to handload, I would definitely check out Holland and Holland's fatory Paradox ammo that they make now for their new Paradox guns. I have heard and seen pictures of someone using this ammo in their Explora. I think it would have to be re-regulated for it though. Not sure if there is any other options beside handloading or the factory Paradox ammo. I am hoping someone else will chime in on this.
If you are looking for anymore info, particularly on handloading, I will let the experts chime in as I have neither owned one of these guns or reloaded for one.
Here is a link to a thread on nitroexpress.com that might help. They talk a little bit about handloads, as well as the LT bullets:
http://forums.nitroexpress.com/showflat.php?Cat=0&Number=71907&page=0&fpart=1&vc=1Charlie