My apologies for resurrecting this thread again, but I got bored and started trawling through old threads...
With the introduction of the Enfield Rifle-Musket in the Crimea from 1855 firing the .568 minie-style Pritchett bullet, the bottom (bullet) end of cartridges containing the bullet and powder was lubricated with a mixture of tallow and bee's wax. Pure bee's wax was too hard and needed to be softened with tallow in order to ram down the lubricated, paper-patched bullet. (The problem was ultimately solved by reducing the calibre to .55 with expanding wooden plug in about 1859).
[Most of the following I lifted from Wikipedia, but I feel justified because I wrote most of it]-
The new Rifle-Musket was a contributing cause to the Indian rebellion of 1857. Sepoys in the British East India Company's armies in India were issued with the new rifle in 1857, and rumours began to spread that the cartridges (referring here to paper wrapped powder and projectile, not metallic cartridges) were greased with either pig fat or beef tallow - an abhorrent concept to Muslim and Hindu soldiers, respectively, for religious reasons. British military drills of the time required soldiers to bite open the cartridge and pour the gunpowder contained within down the barrel, as part of the loading process. The musketry books also recommended that “Whenever the grease around the bullet appears to be melted away, or otherwise removed from the cartridge, the sides of the bullet should be wetted in the mouth before putting it into the barrel; the saliva will serve the purpose of grease for the time being."
The idea of having anything which might be tainted with pig or beef fat in their mouths was totally unacceptable to the sepoys, and when they objected it was suggested that they were more than welcome to make up their own batches of cartridges, using a religiously acceptable greasing agent such as ghee, or vegetable oil. But this, of course, seemed to be "proof" that the issued cartridges were, in fact, greased with pig and/or beef fat. A further suggestion that the sepoys tear the cartridges open with their hands (instead of biting them open) was rejected as impractical - many of the sepoys had been undertaking musket drill daily for years, and the practice of biting the cartridge open was second nature to them. Incidentally, after the Mutiny, manuals changed the method of opening the cartridge to “Bring the cartridge to the forefinger and thumb of the left hand, and with the arm close to the body, carefully tear off the end without spilling the powder.”