Army 5.25" Ammunition

[altec]

Couple of illustrations of Army 5.25" Shells and a Cartridge. Does anyone know the function of the "Smoke Box" in the HE Shell, to mark the burst perhaps?

 

[Eggburt1969]

To quote the 1936 publication 'Textbook of Ammunition'...

Owing to the fact that amatol produces little or no smoke on
detonation, with 3 .7-inch and above, smoke composition may be
embodied in the bursting charge (with amatol 40/60 the smoke
composition is contained in a small box at the base of the filling).
Smoke composition may also be employed in trotyl filled shell if
conditions of observation necessitate.

There you go :tinysmile_classes_t

Oh, and from the same publication.

Fumyl is used as a burster and smoke composition in some smoke shell.
Mark II consists of trotyl 45 per cent., ammonium chloride 40 per cent., and ammonium nitrate 15 per cent.
Mark III consists of composition exploding (Grade I) ground 38 per cent., aluminium powder (light) 24 per cent., sodium chloride 35 per cent. and oil, linseed, boiled " lead free," 3 per cent
Mixture, explosive and smoke No. 5, is used as a smoke composition in shell with cold-pressed amatol fillings. It consists of : Ammonium chloride, 30 per cent. ; 80/20 amatol, 70 per cent.
Mixture, explosive and smoke No. 7, is used as a smoke composition in shell with hot-mixed amatol fillings. It consists of : trotyl, 20 per cent. ; ammonium chloride, 40 per cent.; and ammonium nitrate, 40 per cent.
Red phosphorus is also used with certain trotyl fillings to increase the visibility of the burst.

 

[HAZORD]

The U.S. used 4 different colors of smoke charges in their 90mm AAA rounds, so the gun crews could tell which ones were on target.