ITX shot is malleable but unfortunately can be quite abrasive, and must be loaded with adequate bore protection:

http://gunsandammomag.com/cs/Satellite/IMO_GA/Story_C/Retro+Waterfowlers+Delight

This is quite a disappointment, especially in the muzzleloading community. This leaves just Nice Shot/EcoTungsten at the moment, for those who wish to avoid plastic, AFIK.

Regards,
Joel