Another Afghan Jezail?

[Victrix]

This is an antique rifle given to me as a gift 20 years ago, and I always wondered what it was. It was purchased from an antiques shop on Eton High Street (Berkshire, England). The seller said it “was used by British troops in the Sudan.” Recently I saw pictures of similar objects identified as Afghan jezail. It has a functioning percussion lock stamped with a British crown and "Tower 1870." It has a scrolled hexagon barrel with a detachable ramrod stuck in underneath. There's still some black gunpowder in the barrel. The rifle is 141cm long and weighs just over 3kg. The rifle has real patina in my view, and must be old. It has been used, as there are still traces of gunpowder in the barrel and the wood behind the nipple has been burnt away by the mercury used in percussion caps. The ramrod goes all the way down the barrel with a couple of inches left at the top to hold. The nipple is hollow as it should be. I did some reading on Jezails, and the lock may or may not be British made. The trigger and trigger guard look like crude replacements, or suggest local production.

The question is whether this is likely an Afghan Jezail, or were they also made and used in other areas like India and North Africa (Sudan)? Could it have been used by muslim Indian troops in the British Army?