6pdr Hotchkiss tank or Naval round?

[Rrickoshae]

Please see the attached photos of one of my 6pdr Hotchkiss rounds. I had presumed it to be a naval round due to the small N stamped on the base of the case. TO me, corroborated by the naval N on the primer protector which came with it but I accept may not be original to this round. The shell is a MkIV by VSM. But I have been given an alternative opinion that the N is too small to be the naval ordnance mark but is more likely to be a quality or acceptance mark and that the round is a land service example. I am now confused!

Can anyone say for certain that this is a naval or land service round?

many thanks, Dave

 

[Tony Williams]

As I expect you know, Dave, two different versions of the 6 pdr gun were used in the early tanks. The first used a version of the standard naval 6 pdr 8 cwt gun with a 40 cal barrel, but this showed a tendency to dig into the ground so the barrel was drastically shortened to around 23 calibres to create the 6 pdr 6 cwt (this is a dim memory, might not be quite accurate).

As far as I know the 40 cal gun used standard naval ammo, and I don't know whether or not there were any special markings to indicate it was made for army use (I suspect not, at least initially). The 23 cal gun had the propellant load drastically reduced for a much lower muzzle velocity (the muzzle flash and blast would have been horrendous with standard ammo) and this was distinguished by having the bottom half of the case chemically blackened. I don't know if there was anything different in the headstamp as well.

 

[HAZORD]

It seems like there was a discussion of the use of the N on cartridge cases a couple of years back. The N could stand for Nordenfelt, if the case/projectile was old enough to be Nordenfelt and wasn't marked by an other manufacturer's code, or it could stand for Navy. But as I remember, if the N and Crow's Foot were together, the N was for Navy.

 

[Rrickoshae]

thanks Tony/Hazord. As you say, the initial supply of rounds for the tanks would have come from naval stocks and would have had the 'normal size' N but by 1917 naval and land services may have each been placing their own contracts. Also, the primers are 1914 dated which would tend to suggest a naval round but as with the primer protector, I can't be sure that they are original to this round. The case manufacturer is Royal Laboratories and they are not reloaded cases. We'll have to see if anyoine else comes up with a theory! thanks, Dave

 

[AE501]

There were many variants of 3pr and 6pr during WWI and before. The same cart case marks and primer could be found marked for use by both RN (N)and the Land Service (L). The same combinations could also be marked 'C' denoting that it could have a projectile common to both 'N' and 'L'.
Yours is a Mk III* case with a Primer No 2 Mk III.
There is only one item in this combination marked 'N' and that is the one shown in the table, shown for use with 6pr Sub Calibre. All the other Mark III* cases have a Mark I or 2 primer No 2, with the exception of another 2 cases which are 'C'.
The only way you could ever really tell which case had which projectile was by knowing the propellant weight.
All this was at 1915 (see Treatise) but there was probably not much more variation, there being quite enough already.
Your arrow and 'N' combination is clearly shown in the attached stylised cart case base drawing, accompanied by every base marking possible for QF carts at that time (1923).
While it was usual to put a big 'N', quite often at 3-15am/pm, this would be a bit self defeating if you had marked a lot of one variant only to find you needed one of the other variants. Far better to have a stamp made up for each variant with the broad arrow and use them as required, in a fly press or similar.
The pair on yours are of similar size (see drawing) and the strike depth is notably similar.

 

[Rrickoshae]

thats really excellent AE501 and answers the question beyond reasonable doubt. And I'm sure many others will find your posting of much interest.

many thanks indeed.

Dave

 

[BMG50]

Are these tank 6 pounder projectile difficult to come by as I am looking for one for a case I acquired a while back.

 

[Rrickoshae]

Are these tank 6 pounder projectile difficult to come by as I am looking for one for a case I acquired a while back.

a projectile on its own is now probably harder to find than a complete round as shell & cases will have been mated up by collectors over the last few decades. But it shouldn't be too hard to find a dealer with a complete round for sale. Dave

 

[AE501]

Dave
Further to my comment. I assume you noticed that your steel shell Mark IV matched the possible Marks III, IV and V for that table item.
Bill

 

[Rrickoshae]

hi Bill, yes thank you. These came as a pair and were totally identical including the 1914 dated primers so I don't think they are 'made up' rounds although the base fuzes are not the plugs one would expect to see with a sand or salt filled shell. Presumably sub calibre could also be used with live shells.

regards, Dave

 

[AE501]

Thinking in reverse, it is better to take shell which you would normally fill for live use, probably HE and use those, rather than make a special shell.
For our ranging purposes representing a much larger calibre gun, probably 12" to 16" in the case of 6pr sub cal, it would be critical to weigh the shell accurately before filling them with a known substance and the same again after filling.
You then have a range table for the sub calibre gun, representing the distances that the main arm has been set to fire at.
Bill

 

[Gspragge]

This may help, though it's all out of order ?