When the Americans got involved in World War One, they built a whole whack of M-1917 Browning HMGs, sent them to France and then discovered that their fine theories as to what the .30 M-1906 SHOULD do were considerably at variance with what they actually WOULD do. A purchase ensued of 173-grain BT bullets from the Swiss and things were underway for the development of the Ball Cartridge, caliber .30, M-1.
The British, in their unimaginative, plodding manner, tested the rifles and the ammunition together BEFORE manufacturing umpty-zillion sets of sights.
The end result is that you can aim the British rifles and they WILL hit what you are shooting at, at any range, if you have a rifle in good order, hold it right, dope your wind correctly and have ammunition duplicating the Ball specifications for the period in which your rifle's sights were set. For rifles made from 1910 until the end of .303 rifle production, this was the Ball Mark VII round, which used a flatbased 174-grain bullet of 3-piece construction with rather a long ogive and left the rifle at a nominal 2440 ft/sec.
The problem today is that no-one on this part of the map manufactures the Mark VII bullet. They ARE still in production in India and Pakistan both and likely in other countries as well, but nobody is importing them. SIERRA makes a nice 180 flatbase in their Pro-Hunter series and this is a good accurate bullet in most rifles with Enfield rifling. Its 6 extra grains of weight is not much of an issue and can be overcome. The problem is with its SHAPE. You can start it off at 2440 allright, but it does not buck the air as well as would the Mark VII. It can't, because its ogive is the wrong shape. To manufacture a bullet with a lead or lead/antimony core for the .303, and have it the same shape and the same length as a Mark VII, would result in a bullet of something like 200 grains' weight. That internal aluminum/paper/plastic/compressed doggie doodoo/whatever tip does a lot of things all at the same time. It gives the bullet the length it needs to flow through the air efficiently and it keeps the weight down. It also rebalances the bullet for more accurate shooting as well as for a certain amount of impact-instability AND it reduces the overall specific gravity of the projectile. The Mark VII bullet is a complex piece of very excellent engineering and it cannot be duplicated precisely in any other manner.
I would think that if it were possible to get some and then re-shape the tips, that Winchester 180 Silver-Tips might serve as the basis for a "Mock Mark VII".
The best solution, though, would be to ask very nicely if Greenwood and Bately or Crompton-Parkinson or someone might run us off a batch of Service bullets. Ideal would be Trade-Ex or Marstar importing a few tons of REAL ones from Ishapur or Dum Dum or POF in Wah Cantt.... and then putting them out at prices we can afford.
THEN we could all go to the range.
Five bucks sez the old Smellie outshoots the Number 4 at 1000 and another five sez the Ross outshoots them both!