I shoot a 2400 FPS load in my Yugo 24 47, but it takes 44.0 Grains of IMR 4895 to achieve this with a Speer Hotcore 150 Grain Spitzer Bullet.
The 44.0 Grain Powder Charge is the starting load in my Complete Load Book for the 8MM Mauser. Im satisfied with that load, no need to waste more powder in an iron sighted Rifle. To the OP, be carefull with your reloading for the .303 Enfield. The chambers often run a little long on those, and sometimes the headspace is questionable, its best to only full leingth resize new cases, then after firing in your Rifle, neck size only. let the brass expand to fit your chamber, and you will be less likely to rupture cases. Good Luck.