https://en.wikipedia.org/wiki/Causes_of_the_Indian_Rebellion_of_1857

[raykeller]

https://en.wikipedia.org/wiki/Causes_of_the_Indian_Rebellion_of_1857
The Enfield Rifle
The rebellion was, literally, started over a gun. Sepoys throughout India
were issued with a new rifle, the Pattern 1853 Enfield rifled musket-a more
powerful and accurate weapon than the old but smoothbore Brown Bess they had
been using for the previous decades. The rifling inside the musket barrel
ensured accuracy at much greater distances than was possible with old
muskets. One thing did not change in this new weapon - the loading process,
which did not improve significantly until the introduction of breech loaders
and metallic, one-piece cartridges a few decades later.

To load both the old musket and the new rifle, soldiers had to bite the
cartridge open and pour the gunpowder it contained into the rifle's muzzle,
then stuff the paper cartridge, the cartridge itself was overlaid with a
thin mixture of beeswax and mutton tallow for waterproofing, into the musket
as wadding, the ball secured to the top of the cartridge and guided into
place for ramming down the muzzle by the paper cartridge being used as the
wadding. The rifle's cartridges contained 68 grains of FF blackpowder, and
the ball was typically a 530-grain Pritchett or a Burton-Minié ball.

It was believed that the cartridges that were standard issue with this rifle
were greased with lard (pork fat) which was regarded as unclean by Muslims
and tallow (cow fat) which angered the Hindus as cows were equal to goddess
to them. The sepoys' British officers dismissed these claims as rumours, and
suggested that the sepoys make a batch of fresh cartridges, and grease these
with beeswax and mutton fat. This reinforced the belief that the original
issue cartridges were indeed greased with lard and tallow.

Another suggestion they put forward was to introduce a new drill, in which
the cartridge was not bitten with the teeth but torn open with the hand. The
sepoys rejected this, pointing out that they might very well forget and bite
the cartridge, not surprising given the extensive drilling that allowed 19th
century British & Indian troops to fire three to four rounds per minute.
British & Indian military drills of the time required soldiers to bite off
the end of the Beeswax paper cartridge, pour the gunpowder contained within
down the barrel, stuff the remaining paper cartridge into the barrel, ram
the paper cartridge (which included the ball wrapped & tied in place) down
the barrel, remove the ram-rod, return the ram-rod, bring the rifle to the
ready, set the sights, add a percussion cap, present the rifle, and fire.
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"
This meant that biting a musket cartridge was second nature to the Sepoys,
some of whom had decades of service in the Company's army, and who had been
doing musket drill for every day of their service. The first sepoy who
rebelled by aiming his loaded weapon at a British officer was Mangal Pandey
who was later executed.[22]