As the
time and percussion M99 for 7cm shells was dedicated to the mountain guns of this caliber, a seconf family of the M99 fuze type was developped specifically for the 10cm howitzers : the
time and percussion fuze SDZ M99 10cm for the schrapnell shells, the
time and percussion fuze GDZ M99 10cm for the high explosive shells, and the
time and percussion fuze M99a or M99b 10cm for the star shells.
The M99 fuzes, both for the 7 cm or the 10 cm shells, and throughout all their versions, were internally organized on the same principles introduced by the preceeding time and percussion fuzes and from now on classical : In the basic
SDZ M99 fuze, a time system with two discs (the lower being mobile), a concuting system housed in the fuze head and secured at rest by a safety pin, and in the tail a percussion system secured at rest by a mobile safetyu cylindrical ring that was pushed back at the shot departure and a weak safetyu spring located between the static percussion pin and the mobile graze pellet bearing the percussion cap. A small detonator rod was attached to the fuze base.
The variant
GDZ M99 was designed on the same basis, but was equipped with a big detonator gaine in order to be able to detonate the high explosive shells ('Ekrasite'), and the selactable 'K' (cannister behavior) was suppressed (no one wanted a high explosive shell to detonate at the muzzle outburst...). The variants
M99a and
M99b for star shells were following the same design, without detonator gaine, with time graduations expressed in fractions of the total combustion length units, and the selectable 'K' (cannister) and 'V' (delayed explosion at 200 m from the muzzle) were both suppressed
The shape of these fuses was pretty aerodynamic and similar to the rotating discs type time and percussion fuzes of many other nations. I do not have any documentation on the thread sizes of these fuzes and shells.
The markings on the mobile disk were proposing the different behaviors :
- Time behavior with in-flight explosion - selected by one of the time ring scale graduations at a distance from 4 to 56 hundreds of meters with 50 meters subdivisions. In the case of the M99a and M99b versions, the graduations were spreading from 0 to 25 with 1/4 subdivisions, that is a total of 100 graduations representing each 1/100th of the total length of the time fuzing composition track.
- Percussion behavior with explosion at the impact - selected by the 'A' ('Aufschlag') letter
- Cannister with explosion at the gun's muzzle exit - selected by the 'K' (Kartätschrapnell) letter, for the version 'SDZ M99' for schrapnell shells only.
- Cannister with delayed explosion at 200 m of the gun's muzzle exit - selected by the 'V' (Vortempierung) letter, only for the version 'SDZ M99' for schrapnell shells and the version 'GDZ M99' for high explosive shells .
The SDZ M99 10cm fuzes were used with the schrapnell shells of the :
- 10 cm M1899 and M1914 field howitzers
- 10 cm M1899, M1908, M1910 and M1916 mountain howitzers
- 10 cm M1899, M1905, M1906 and M1909 fortress howitzers under cupola
The SDZ M99 10cm fuzes were used with the high explosive shells ('Ekrasite') of the :
- 10 cm M1899 and M1914 field howitzers
- 10 cm M1899, M1908, M1910 and M1916 mountain howitzers
- 10 cm M1899, M1905, M1906 and M1909 fortress howitzers under cupola
The M99a were used with the star shells of the :
- 15 cm M1894, M1899, M1899/04, M1899/04 and M1915 heavy field howitzers
- 15 cm M1894 and M1899 fortress howitzers under cupola
- 15 cm M1880, M1898, M1898/07 and 1916 mortars
- 15 cm M1880 fortress mortars under cupola or on sledge mounting
- 21 cm M1880 coastal defense mortars
- 21 cm M1916 mortars
- 24 cm M1880, M1898, M1898/07, M1895/10 and M1910/15 mortars
The M99b were used with the star shells of the :
- 10 cm M1899 and M1914 field howitzers
- 10 cm M1899, M1908, M1910 and M1916 mountain howitzers
- 10 cm M1899, M1905, M1906 and M1909 fortress howitzers under cupola