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The original .303" MkVII bt weighed 160 gr and was approved in Mar 1910 and had no cannelure. Production lots of this ammo failed accuracy proof and the bt was redesigned.
The new bt retained the exterior dimensions of the above but the aluminum core tip was shortened and the lead lengthened. The new bt weighed 174 gr and was approved LOC 15629 Oct 1910.
".303Inch" Labett and Meade

[CINDERS]

Yeah Green the Drawing from the SAC is dated 1909 wonder what the short comings were in the accuracy the Brit's were big on long range beaten zones weren't they hence the volley sights is there any literature you may have about the tests Green!

[Alan de Enfield]

Yeah Green the Drawing from the SAC is dated 1909 wonder what the short comings were in the accuracy the Brit's were big on long range beaten zones weren't they hence the volley sights is there any literature you may have about the tests Green!

Here are the comparisons of the 'new' Short Rifle (SMLE) with some of the competitors - showing what Figure of merit each could achieve.
Dated 1904 source "Rifle Mk1 Short" Report written by the Director Of Artillery

[Bruce_in_Oz]

Note the aluminium inner "cap", in both the "experimenta"l bullet and in ALL Mk 7 bullets.

Somewhere along the line, it was decided to make the overall bullet length similar to the Mk 6.

It was also a mechanical requirement to have an overall cartridge length VERY similar (and no longer than) Mk 6, otherwise a LOT of small arms, particularly machine guns and most importantly maxim and Vickers Belt-fed types, would r4equire re-engineering of their feed system components.

By designing a "spitzer" bullet, a lot of weight went away, nut not quite enough, Hence the internal lightweight "cap". The boffins had settle on the concept of a high-velocity bullet and a spitzer shape was a good start. Shaving a bit more weight of would get the muzzle velocity and hence trajectory they also wanted.Because the Mk 7 retained the length, the RIFLING twist of 1:10 inches was, conveniently "a good thing".

That the bullet was "base-heavy" and thus destabilized on transition from air to more "wet" targets, the "body-counters" were probably overjoyed that terminal results were suitably gruesome even though the bullet met all the conditions of the Hague Convention. While forward "velocity is shed rapidly in flight, the ROTATIONAL rate of a bullet barely changes after leaving the muzzle., so, being struck by a Mk 7 bullet, at extreme MG ranges, and thus subsonic, will DEFINITELY 'leave a mark".

Interestingly, Mk 8 bullets do NOT have that lightweight inner cap, but they have a reasonable "boat-tail" Hence a weight of 180 gn, and the boat-tail contributed to less dispersion at trans-sonic and subsonic speeds. . Derived from pre-WW2r experiments with bullets for long-range target shooting.

[CINDERS]

So Bruce the Mk8 Z'eds were exclusively for the mg's to give a good beaten zone at extreme range so they went up 6 grains are the 8'd loaded any hotter than say the MkVII ball ammo.
I have read what you speak of in relation to the wound characteristics of the MkVII ball round it definitely had an impact whether by design or fluke how its dynamics worked when deforming and tumbling inside.

[Alan de Enfield]

So Bruce the Mk8 Z'eds were exclusively for the mg's to give a good beaten zone at extreme range so they went up 6 grains are the 8'd loaded any hotter than say the MkVII ball ammo.
I have read what you speak of in relation to the wound characteristics of the MkVII ball round it definitely had an impact whether by design or fluke how its dynamics worked when deforming and tumbling inside.

MK8s were 'primarily' used for MGs but their use was also 'allowed' in rifles 'Stens' etc whilst doing night patrols (due to the reduced flash of the NC)

[browningautorifle]

also 'allowed' in rifles 'Stens' etc whilst doing night patrols

You meant Brens?

[Alan de Enfield]

You meant Brens?

OOOOPs !
Yes

Should have quoted the regs instead of relying on my memory.

[Bruce_in_Oz]

I was under the impression that Mk 7 Z started out in the aerial gunnery biz, Cordite has a well-earned reputation of muzzle flash, granulated Nitro-cellulose, less so. A tail-gunner in a 4-gun Lancaster turret would be dazzled by his own muzzle-flash if "standard" Cordite ammo were used. I also suspect that the "Z" used in Mk 8 Z was a bit slower-burning than Cordite; better for use with marginally heavier bullets in longer MG barrels.

In the First Great Unpleasantness, US factories NEVER used "Cordite to fill .303 ammo for Britain,instead, they used the same type of stuff they used in their "sporting' ammo in that cartridge.. The Canadians made BOTH styles of ammo; Mercuric-primed, Cordite-fueled stuff at the "government" facilities and Boxer-primed, NC powder-fueled at "commercial" plants.

US factories also churned out vast amounts of 7.62 x 54R and 8mm "Lebel" in WW1. As long as it was reliable and had similar ballistic behaviour, it was acceptable. The subtleties of variations possibly affecting performance or whatever, were irrelevant.

Some of that WW1-vintage, US made 7.62 x 54R ammo made it to Oz in the late 1970s. Good stuff, especially in Tokarevs. which, in the "good old days' were more common here than Mosin Nagants.

[Daan Kemp]

Having shot thousands of military 303 through several No 1 and No 4 rifles, I have never seen a muzzle flash. Granted, my shooting has never been in the dark, only low light every now and then. Or my eyes are deceiving me, which is entirely possible.