40mm Bofors Cast Iron Break Up Shell?

[Darkman]

I picked up this unusual Bofors shell recently. Initially I thought it may have been an SAP projectile, but strangely it’s made of cast iron and is completely hollow with a zinc base plug. Also marked BU and Mk VIII. Maker is General Motors Holden’s, Woodville, South Australia (GMHW).

My next thoughts were that it was possibly a practice shell, with BU something to do with Bitumen filling for weight, but it doesn’t have a “P” stamped on it anywhere. Then I thought BU could be something to do with break up shot, like the later Bakelite type, as cast iron is quite brittle. But I’m really quite stumped as I can’t find any reference in any of the Bofors handbooks or ammunition manuals, and apparently there are 7 previous marks!

Note that member Burney Davis has a near identical British shell also stamped BU and dated 1942.

Can anyone identify this shell or have any information on it at all?

Thanks, Graeme

 

[Gspragge]

It's nice and shows up on the chart-

 

[Darkman]

It's nice and shows up on the chart-

Thanks Gordon! Quite likely a Break Up shot then.

 

[Kilroy]

Knowing how sensitive cast iron is to certain types of stress, I look at the depth of the marks on the projectile and am surprised that they would have gone with roll marking the relevant data on the shell itself, and not instead gone with a stencil stamping that would *NOT* have subjected the outside of the shell to a possibly crushing force that could have resulted in a pile of broken fragments and black dust!
Walt

 

[TimG]

Actually, cast iron is very good in compression.

TimG