After the landmark success of the Enfield-Gibbs, the British Ministry of War decided it was appropriate to try a hand at taking this remarkable new technology and applying it towards an IAC, or "Infantry Automatic Carbine", which by definition are shorter and capable of fully automatic fire Rather than the semi-automatic or "paced" rates of fire of the IAC's larger and usually either repeating fire based or bolt-action counter-parts. With Gyrojet technology essentially being proven as a viable route for British weapons technology to pursue it was agreed that Enfield would once again be proceeding with further R&D into the Gyrojet weaponeering field.
Litterally picking up where the Ministry of War told the Enfield Gyrojet R&D department to stop; it took them only a year to refit and re-design the .303 cartridge (The Empires Previous standard issue cartridge) into a Gyrojet munition. Keeping the extreme-high tensile friction scraping "matches" on the casing and re-designing the round into it's terrifying new format "HVDP" or "High-Velocity-Deep-Penetration". The Rounds are tungsten-cored soft-steel jacketed "center-points" with an almost absurd amount of cyclonic energy being released from the barrel once the round discharges and it's "rocket" kicks in after the "Scrapers" proceed to ignite the cartridge.
The weapon is equipped with a twenty-five round detachable box magazine, it's lethal-beyond compare in regard to what a soldier can have either in a trench or an urban combat zone. It's rate of fire can actually be likened to that of a Sten submachine-gun from our own timeline. Many English soldier's call this weapon "George", after "Mad King George" due to the fact that it's so as to quote a First Sergeant of the Royal Marines "It's a bloody-barking mad weapon, but it's still the king in our trench!".
The British Empire's Confederate Allies were offered a chance at utilizing Gyrojet technology, they of course declined, then made a concession and so as to quote Earl Kemps Long, the Confederate Minister of War :
"I find this new bullet o' yours to be a might bit queer, no offense intended but I suspect the men who fight under the Stars & Bars would prefer to just stick with the .303-Longstreet, it's cheaper to produce and easier on the soldier, after all, I myself fought in the 1906 Border-War, thusly I can attest to the .303's capability. As such, we are content with our current cartridge."
The British Minister of Defense responded in kind with the following Letter:
"Mr. Long, I understand your concern about a "newfangled" design, but please understand that we offer this stunning new munition in good faith and conscience unto our foremost allies, we have proven the rounds capabilities against the Swedish in south-east asia, it terrifies them, if anything, please take this munition as an anti-aircraft device. My Colleagues are insisting that I push the offer because we (as in the Imperial Ministry of Defense) are concerned that other nations may be gaining technological breakthrough's of different kinds and capabilities. We insist further because we want our allies upon even footing with the Bosche-Union Entente."
The Confederate Minister of War instead made it compulsory to have .303 Gibbs-Gyro made as a specialty munition amongst Confederate Troops. It was proven to be capable of being loaded AND fire from the CSA's Battle-Rifle's and IAC. Which of course proved to be a boon to Confederate Moral.