The Chergui

Timeframe: October 1895-April 1896.
Belligerents: The Crown of All Spains vs. Mahdist insurgents.
Outcome: Pyrrhic Spanish victory

In 1893, Yusuf II was faced with a small nightmare: a military standards war. It took the better part of a year to sort it out, and no small investment of money and man-hours, before the Caliphal Army was uniformly issued matching rifles and ammunition that wouldn't explode. The Port-Royal musketoon had prevailed, and the army now faced a problem: what to do with all the noncompliant hardware?

Refitting it was too much trouble; they already had their hands full retooling sights, adjusting barrel lengths, and making similar conversions on thousands of already-assembled guns. Issuing them down the totem pole would force the very logistical nightmare they'd just spent 15 months sorting out. Issuing them to the navy might work, but would still be a logistical headache. (More importantly, the Army Secretary thought the Navy's adoption of .49-94 a decade prior a smashing political victory, one he had no desire to undo.) This being the UCNA, they'd already rechambered a number of obsolete guns for the rejected H11 cartridge - proofs of concept, substitute standards, all sorts of stuff.

The fateful solution was to sell the useless crap abroad.