@sgdbdr No, unfortunately they aren't. The first two drawings are from the library of the National Military museum in Bucharest while the third comes from my collection.
@MINENAZ16 and
@doppz92 - the 202mm lenght pretty much confirms it to my mind, because there's a phenomenon I've noticed with the
French made 53mm Gruson shells that seems to be repeating - in 1915 we needed to manufacture a new HE shell for these old guns after it was decided to take them out of the forts and put them on wheeled carriages, and we chose to do it by fitting the fuze from the 75mm Md.1904 Krupp onto the body of the old black-powder filled common shells. Since the Md.88 nose fuze common to both the 53mm Gruson and the 57mm Hotchkiss is 22mm in diameter and the Md.04 fuze is 31mm, an expedient solution was just cutting down of the ogive to the new diameter, which meant that the Md.15 HE shells for both guns were a few millimetres shorter (8mm in the case of the 53mm Md.87 and 11mm in the case of the 57mm Md.88).
However, when it came to making shells from these guns in France, the French manufacturers were given the height of the original common shells, so the French produced projectiles ended up taller than the Romanian made ones.
The height of the Romanian 57mm Md.88 black-powder filled nose-fuzed common shell is
203mm without fuze as per the manual. This squares very well with a measured height of 202mm without fuze for this example. By comparison, the height of the Romanian made 57mm Md.15 HE shell is 192mm without fuze, 11mm shorter.
So, if it looks like a duck and it quacks like a duck...
I am also baffled by those wrench slots - it would make sense for them to be there if the projectile was like the drawing I posted, with a removable ogive, but it seems it's not. What does the inside look like? Also, what is the distance from the driving band to the bourellet? I want to compare that with the plans, since it should be 69-70mm.
Finally, about the cartridge case, unfortunately, nobody I know has even seen one, let alone have one in their collection and I've been looking for the last few years without success.
However, we do have blueprints for the cartridge, so I was able to 3d print a replica.
It's dimensionally identical to the British naval QF 6-pounder case (itself originally a Hotchkiss design), but cut at 231mm in height and necked down to 57mm.
When it comes to the headstamp, it helps that Romanian headstamps from about 1910 onwards were very simple and consisted of only the year and a three-letter code begining with "P.A." which stands for "Pirotechnia Armatei" the Army Pyrotechnics facility which operated in Bucharest from 1880 to 1950. We're not sure about the third letter, but the code for 1913 seems to have been "PAH" while that for 1915 was "PAL" - if one assumes these were alphabetical and changed each year, that means two letters were skipped over, so another hypothesis is that it means the origin of the metal used to make the case such as "H" being "Hirtenberger", "L" being "Lorenz", etc.
Interestingly, all cases, regardless of calibre, used the same 6mm tall markings, as can be seen from this comparison of a cartridge case from the 53mm Gruson and one for the 75mm Krupp.
