My enfield loves this ammo - PPU PP303F Standard Rifle 303 British 174 Gr Full Metal Jacket (FMJ)

This 174gr FMJ and the 180gr SP from PPU is the only 303 ammo I can find that can do 2 MOA or better from my No4 Enfield which is the standard of accuracy from those rifles. The case heads are also beveled properly for correct feeding unlike other brands 303. It being some of the cheapest 303 available and always in stock is a nice bonus.