4.2 INCH MORTAR

[WAKEN]

The British Ordnance ML 4.2 inch mortar fired a 20 HE bomb. Does anybody know what the weight of explosive filler was?

[rcocean]

The British Ordnance ML 4.2 inch mortar fired a 20 HE bomb. Does anybody know what the weight of explosive filler was?

Assuming it was similar to the US 4.2 inch mortar - From US Army History:

When the CWS received permission to use HE, munitions experts modified the standard shell slightly, removed the vanes and burster tube, and then loaded the missile with TNT. An HE shell with fuze weighed 22 lbs and the explosive charge weighed 8 lbs. This quantity of TNT, approximately one-third of the weight of the filled shell, represented a high loading efficiency, and the blast and fragmentation effect of the shell upon impact was tremendous. In September 1942, the CWS standardized this shell as model M3.

[WAKEN]

Thanks for that. I already have the data on the US 4.2 inch mortar bomb. The weight of explosive filler for the UK 4.2 inch bomb is proving elusive...

[Alanmccoubrey]

Have you thought of directing your "filler" questions to the Artillery Museum at the Rotunda in London ?

[Fatboy Coxy]

Theres a nice web site showing the types of mortar bombs used for all the British mortars here
http://visualcollector.com/VisualCollec ... sMines.htm

And a bit here about production numbers
http://www.wwiiequipment.com/index.php? ... &Itemid=59

Steve

[wwilson]

I'd like to bump this topic as the question regarding the bursting charge weight and type was never answered.

Or, put another way, does anyone have a copy of "Ammunition Bulletin No 29" they could share with this forum ?

Thanks.

Cheers

[Gary Kennedy]

From the February 1944 handbook on the 4.2-inch mortar (available from MLRS books as a download).

HE bomb (with No.1 tail) - weights in lb/oz/dram

Filling - 4 / 3 / 7
Fuse - 0 / 12 / 10
Total - 20 / 9 / 0

Streamline I bomb (with No.2 tail) - weights

Filling - 2 / 11 / 4
Fuze - 0 / 12 / 10
Total - 19 / 10 / 6

Streamline II bomb (with No.2 tail) - weights

Filling - 3 / 2 / 0 or 3 / 3 / 1
Fuze - 0 / 12 / 10
Total - 19 / 13 / 7 or 19 / 14 / 8

There are a lot of British Ammunition Bulletins on bulletpicker.com but not No.29 it seems.

https://bulletpicker.com/ammunition-bulletins.html

Gary

[wwilson]

Mr. Kennedy,

Thanks so much. I've bookmarked that site. Yes, I was a bit frustrated that the bulletins on the bulletpicker site stopped at #28, heh.

Cheers!

[wwilson]

So, in metric terms, the bursting charge weight for the 4.2-inch mortar HE shell appears to have been about 1.9118 kilograms.

Bursting charge weights in HE shells for other mortars:

3-inch: about 0.5185 kilograms

2-inch: about 0.1616 kilograms

The source for the last two is Ammunition Bulletin No 4 (after conversion from pounds/ounces/drams to metric units).

Cheers