I thought I would share this recent acquisition a British 25.4mm. The case has no headstamp, the projectile is stamped 25.4 m/m VSM (Vickers Sons and Maxim) The only information I have about it is in Peter Labbett’s book British SAA 1864-1938 page 308 (thanks Tony E). if anyone has any further information I would much appreciate it.
Buster
Labbett gives a case length of 146mm and a rim diameter of 34.56mm.
The headstamp of the case illustrated in Labbett is:
25.4 m/m SC (12 o’clock)
VA (3 o’clock)
1932 (6 o’clock)
Labbett states that the meaning of SC is unknown, but that VA means it was made by Vickers Armstrong. He had no idea of its intended purpose.
This does ring a small bell for me. In the interwar period there was a brief fashion for infantry artillery pieces which came with two barrels in different calibres, to be swapped according to the target: a small-calibre high-velocity barrel for anti-tank use and a larger-calibre low-velocity barrel for lobbing HE shells. I think that there were various combinations of calibres, but I have a recollection that there might have been such a Vickers gun with calibres of 25mm and 70mm. If so, that’s the most likely candidate. Edit to add: there’s a Tanknet thread on such guns here: 208.84.116.223/forums/index.php?showtopic=35813
Incidentally, that Vickers 25.4mm designation was applied to various cartridges. See my article here for a couple of others: quarry.nildram.co.uk/Vickers25.4.htm
Buster, I’d like to update that article by including the pic of your round, if that’s OK with you.
Hmm - the plot thickens. I’ve just done a bit of digging in my files and come up with an Ordnance Board note dated 25/11/31 concerning some correspondence with Vickers over their “1 inch automatic gun”. In response to questions from the OB, Vickers responded with the following information:
[i]"1 - The estimated weight of the gun with a 60-calibre barrel will be 210 lb
2 - The type of action is the usual barrel recoil operated mechanism of the Vickers system with belt or link feed.
3 - The cooling arrangement is by water contained in a water jacket similar to the Vickers R.C. gun [rifle calibre?]
4 - The gun will fire at the rate of 200 rounds per minute.
5 - The inboard length of the gun will be approximately 36 inches.
The types of ammunition proposed for this gun are:
This is clearly a completely different gun from the 25.4mm naval AA gun supplied to Argentina which is described in my article, as that was gas-operated, air-cooled and magazine-fed.
So…your cartridge might be for the dual-calibre artillery piece, or this automatic gun, or both!
Ordnance Board Memo B 6,412 of August 1923 makes the first mention of a proposed .8 inch automatic gun for aircraft observers and gives a specification. By March 1924 the Board was discussing a .9 inch autmatic gun, both these designs being by Elswick Ordnance Co, part of Vickers.
Later the same year Memo B 8,049 is headed “Aircraft Armament . Tracers, shot, 0.8 inch and 1 inch. design DD/L/1509” and talks of modifications to the shell driving band and asks Superintendent of Design to make 10 steel cartrdige cases to Design DD/L/1447.
The following Memo, B 8.050 talks about .8 inch and 1 inch “Aiming rifles” for the QF 4.7 inch gun. However, this appears not to be an aiming rifle in the sense of a training device but more of a dual calibre gun as TonyW describes. It states “It is thought the gun will seldom be used against armour plate, unless perhaps agianst tanks which would be a very special use. The weight of armour necesary to keep out a 0.8 inch or 1 inch bullet would probably be prohibitive in aircraft.”
It is unclear if the 1 inch cases are the same in both memos, but it seems likely.
I found no further mention of the 1 inch gun and the 0.9 inch gun was disposed of in 1925 although work on the .8 inch Aiming Rifle continued. However, Vickers may well have continued work on the 1 inch as a private venture.
One interesting comment is a note from Elswick to the Ordnance Committee that appears in Memo B 8,720 of April 1925 “As you are aware we have now adopted manufacture of the Colt automatic gun which it appears to us will fulfill the requirements of an automatic gun firing 0.9 inch ammunition.” I though at first this might be the .50 Browning (or Vickers-Armstrong Colt as they called it), but the O.C. replied “…I have no knowledge of the 0.9 inch Colt gun”.
Regards
TonyE
P.S> Yes, Tony, “R.C.” is “rifle calibre”.
Thanks for that, but I’m a bit puzzled by this bit:
I cannot realistically see a dual calibre gun combining 4.7 inch and 1 inch calibres, nor any purpose in such a thing if it “will seldom be used against armour plate”.
Thanks for all you replies. Firstly, my apologies I have misled you all in that the round is not that shown in P Labbett’s book as the case length is 112.45mm. The rim is 34.35mm in diameter.
Tony W, yes you may use the photo in your article.
I have attached another 2 photographs.
Thanks Buster - the plot thickens even more!
It seems amazing today that arms companies would keep churning out multiple cartridges in any particular calibre, just to see if they could sell them. Nice for the collector - except that most of them never left the experimental phase and are very poorly documented, so even if you’re lucky enough to find one of these it can be very difficult to discover what you have.
I have just updated my web article on the British 25.4mm guns and ammunition: quarry.nildram.co.uk/Vickers25.4.htm
Edit to add: as I mention in the article, the 25.4/70mm dual-calibre gun worked by having the smaller barrel sliding inside the larger one, like a sub-calibre training barrel.
So perhaps the “SC” on the headstamp of the 25.4x146R in Labbett’s book stands for “sub-calibre”?
[quote=“TonyWilliams”]Thanks for that, but I’m a bit puzzled by this bit:
I cannot realistically see a dual calibre gun combining 4.7 inch and 1 inch calibres, nor any purpose in such a thing if it “will seldom be used against armour plate”.[/quote]
Whilst that may be so, I can only report what is in O.B Memo B 8,050 and there is no further information other than it is headed “AIRCRAFT ARMAMENT” and “Plate trials of projectiles” so it is obviously not a training device. Regrettably my mind reading powers have diminished with age!
The change to metric seems to have happened around 1927 as I have Kynoch drawings for the 1 inch Aiming Rifle headstamped “Vickers 25.4mm”. This is also the date that Vickers merged with Armstrongs.
With regard to the 25.4mm automatic gun, I have two dawings for projectiles, one a conventional bullet and the other a shell with driving band, both dated 1934. See below.
Then, just to confuse matters, here is another 1 inch Aiming Rifle round, but longer than the normal British military type. It just happens to be 25.4x112R. Who used that?
Regards
TonyE
[quote=“TonyE”][quote=“TonyWilliams”]Thanks for that, but I’m a bit puzzled by this bit:
I cannot realistically see a dual calibre gun combining 4.7 inch and 1 inch calibres, nor any purpose in such a thing if it “will seldom be used against armour plate”.[/quote]
Whilst that may be so, I can only report what is in O.B Memo B 8,050 and there is no further information other than it is headed “AIRCRAFT ARMAMENT” and “Plate trials of projectiles” so it is obviously not a training device. [/quote]
A 4.7 inch gun under “aircraft armament”? Stranger and stranger!
Well, in the OB minute I quoted Vickers was still talking about a “1 inch automatic gun” in 1931. On the other hand, they do seem to have been rather casual about nomenclature, since in one of the drawings you have shown the paper is titled 1" but the headstamp is 25.4mm…
Are these definitely for the 1" automatic gun described in the 1931 minute?
Heaven only knows…
Tony - I should have added that there is no indication whether the conventional bullet and the “Shell Q.F.” were intended for the same weapon, or even if either was for the weapon from the 1931 trials.
I also have drawings from the same period for the .75, .8, .866 and .9 automatic guns and of course the Royal Navy started work on the .661 inch soon after. It seems there was a lot of interest in these heavy machine guns at that time, perhaps as competition to the Oerlikon and other cannon beginning to come into service.
Regards
TonyE
