You seem to be confusing marks of ammunition, when it comes to the .303 British round. The original marks were a jacketed round nosed bullet, which was considered unsatisfactory. The design was then changed keeping the round nosed bullet, but cutting the jacketing back around the nose leaving an exposed lead nose - much more devastating performance, and it was found to be more stable in flight. The British also played around with hollow points in this time frame. In the Boer War era things began to change markedly, with the Hague Convention of 1899 making "expanding" rounds illegal as being inhumane. The second Hague Convention of 1907 expanded on things as well. During this timeframe the British had gone up to the Mk.V loading of the .303 British round - and all these rounds were removed from service due to the conventions on the conduct of war. There was also the Mk.VI, which was removed from service due to a lack of performance - it was another attempt at a round nosed thinly jacketed bullet; but the thin jacket did not prove to be successful at causing expansion; shelved...
1910 rolls along, and the British introduce the Mk.VII loading. This is a fully Hague Convention "compliant" bullet design, in the sense that it is an FMJ bullet - and a modern bullet in the sense that it is a spitzer design as well. The British have come up with an ingenious bullet design, though, in which the nose of the bullet is aluminum or cellulose/compressed wood and the base is lead and antimony. What this does is make a tail heavy bullet, which while stabilized in flight due to gyroscopic forces will tumble/yaw significantly when it impacts; causing severe wound damage.
The Mk.VIIz and Mk.VIIIz rounds were boat tailed rounds, with nitrocellulose propellants designed with long range machine gunnery use in mind.
