The British had planned to move to a
.280 calibre rifle prior to WWI, the new rifle was to be the P-14 which was susequently rechambered to .303 as a war time exigency to to supplement the SMLE. The P-14 was produced by Winchester and Eddystone (Remington). Due to a shortage of ‘03 Springfields the P-14 action was redesigned as the P-17 in 30-06. More P-17s than ‘03s were used by American soldiers during WWI. Remington eventuall used the used to P-17 as the basis for the Model 30, a fine rifle. You could still see the P-17 influence 50 years later in the Reminton 660 series with its dogleg bolt handle. It is said that the Remington 700 was an updated version of the Model 30, thus the P-14 - P17 family, but I have not studied to 700 enough to confirm this.
I have a P-17 that was sporterized in the late ‘50s or so with a turned down barrel rechambered to .300 H&H, receiver shaved and new stock. Been changed by me to cock on open and a Timney trigger. Shoots nice groups with 200 gr Nosler Partitions out of that old barrel.
You will want to recheck your historical database.
The British were looking into a .276 caliber cartridge during WW1, not .280. The .280 was the caliber they were looking into after WW2 and the caliber they briefly introduced the post war EM2 rifle in before the whole NATO caliber debacle started.
The Rem 700 is a simplified Mauser 98 action and was based on earlier attempts to make a Mauser 98 cheaper and simpler for more efficient mass production. It is not based on the Enfield P-17 per the designer of the rifle. The 721 the 700 was based on was a clean sheet re-design of the Mauser action to take advantage of the post-War advances in. Mass machining and production. It was not economically sensible to adapt the model 30 to the new tech so they had to start over.