Question about Mk VIIIz ammo

[Longshaor]

Hi all,

I've read that Mk VIII ammo was not supposed to be used in anything other than Vickers MGs due to excessive barrel errosion. Was this also true of the Mk VIIIz? Somewhere or other I've got 3-6 boxes of the stuff...

Cheers!

Information

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[jmoore]

I've fired a few thousand R1M3 rounds which are more or less the same as VIIIz, and like it pretty well. Running out though, and they're not importing any more.



The Privi Partisan everyone likes so well used to be marked .303" Mk.8z as well.


Is it bad for the rifle? It may not do well if it's had a lot of Cordite Mk. VII run through it previously, but aside from that, no dramas. "YRMV"

[fernleaf]

The ONLY difference between Mk7z and Mk8Z was that the 8z had a boat tail bullet for better long range performance out of Vickers MGs. Vickers MGs were issued with two range plates on the sights - one for 8z and one for 7/7z.

The old tale that 8z is bad for rifle barrels no doubt came from Commonwealth soldiers being told not to shoot it in their rifles cause its trajectory wouldn't match the range graduations on the rifle sights.

A similar thing happened to NZ soldiers on Gallipolli - we used MLE Long Tom rifles still with Mk 6 ball, and Kiwi soldiers were told that the Aussie and English Mk 7 ball would not work in their rifles....... it certainly would work, but the trajectory would not match the sights at long range.... How many Kiwis died scrounging for Mk 6 ball when there were ample stocks of Mk 7 ball around? (Info from Gallipolli: the New Zealand Story by Chris Pugsley)

[Thunderbox]

I think current Privi Partizan is indeed their former MkVIIIz that they used to produce for Yugoslavian Vickers guns.

[TonyE]

The OP asked about Mark VIIIz saying that Mark VIII was only for Vickers. There was no Mark VIII, it was only ever nitro cellulose loaded.

The reason that cordite loaded and nitro loaded rounds should not be used in the sasme Vickers barrel is because of different erosion patterns. A Vickers barrel that has only ever fired cordite Mark VII will degrade gradusllay and accuracy will be seen to fall off. A barrel that uses Mark VIIIz will maintain its accuracy and then suddenly fail with no indication. For this reason the barrel life of Mark VIIIz barrels is fixed at 10,000 rounds or 40 belts. This is particularly important if the guns are shooting barrage fire over the heads of friendly troops.

Even a few rounds of cordite Mark VII fired in a Mark VIIIz barrel wil cause the accuracy to drop considerably and the barrel to become unserviceable. For this reason it is forbidden to use cordite loaded tracer mixed with ball Mark VIIIz. It is all to do with the burning properties of the two propellants and the flat based bullets of cordite rounds (Ball, tracer and AP) and the boat tailed bulet of the Mark VIIIz.

These restrictions did not apply to Vickers guns in AFVs which were not used for overhead fire and needed tracer as an aid to aiming. Special belts of mixed VIIIz and tracer were issued marked for AFV use only.

Similarly, as rifle barrels do not reach the temperatures of MG Barrels, the use of Mark VIIIz in rifles was allowed either in an emergency or when less flash was required, e.g. on night patrols.

As an aside to fernleaf regarding the quote from the book about Australian and English Mark VII ammo at Gallipoli, there was no Australian Mark VII ammo. Footscray did not start making Mark VII ball until February 1918.

Regards
TonyE

[Brian Dick]

TonyE has it exaclty right. I learned this first hand with a Vickers and well used barrel that had been fired with cordite Mk.VII. It fired fine with Mk.VII but when we switched to some nice, clean Mk.VIII, the bullets were keyholing at 100 yards. A new barrel from Dolf Goldsmith packed and installed cured the problem.

[fergs]

So when did they actually go into production of mkv11 ammo for our good chaps?, as i was ratting around in an old ammo tin today i found some mkv1 ammo which i purchased with the lighthorse ammo pouch from a gun show some years ago but had forgotten about. Silly old me.

[Bindi2]

MkV11 intrduced: LoC 15629 of 1-10-1911. Approved: 3-11-1910