Smoke box from 3.7" AA HE shell?

[Darkman]

I picked this small bakelite tube up recently and I think it's a smoke box from a 3.7" AA HE shell.

It's about 2 & 3/4" (70mm) long and 7/8" (22mm) diameter. The lid markings are: SMK, 1 1/4 (1 and a quarter), CH (intertwined), I (Roman numeral 1).

An ammunition handbook I have specifies that some 3.7 smoke boxes were bakelite and these were filled with 1oz, 4 drams (1 and a quarter ounces) of smoke composition.

Can anybody verify that it definitely is a 3.7 smokebox?

Thanks,

Graeme

 

[AE501]

There were three main Red Phosphorous Smoke Boxes, 1 + Quarter oz, 1 + Half oz and 2 + Half oz. The most ubiquitous was the 1 + Quarter oz..
To my knowledge it was used in all the early marks of 3.7" AA, 25 Pr, 5.5", 7.2" and 9.2" and probably more HE shell natures.
The one which I was heavily involved with was 25 Pr HE Mk 1. Millions of these were produced with a RP smoke box under a 'B' Bag CE 1 oz exploder. This exploder consisted of 1 oz of CE powder in a rubberised bag, tied at the neck with cord, put in the shell over the first or third smoke box listed ( I do not know how to do subscript/superscript on a Mac Book in Safari without downloading a programme).
It was found that when these boxes cracked and leaked, giving rise to Phosphoric Acid, this reacted with CE and became inflammable.
This lead to huge repair tasks to remove the 'B' bags CE and replace them with a 1 oz CE pellet exploder, over a 1oz 8 dram TNT/Aluminium pellet smoke box.
Those RP boxes that could be removed were destroyed by demolition.