Yes, the chamber of all Enfields used in the tropics were cut to an oval shape. But not to let the Monsoon rain flow out. It let part of the blast out to the rear in order to dry the hair of sepoys. This increased their religious fanaticism and overcame their fear of death. I heard this from a very wise man. It´s TRUE!

PS

Think I´ve got a picture of a fuzzy wuzzy somewhere whose hair is standing straight out just after he´d shot himself in the leg.