Bofors SAP projectile

[Darkman]

I recently acquired this 40mm Bofors Semi Armour Piercing projectile. Quite nice condition, but it has been previously heavily cleaned (possibly to remove rust) which has removed most of the markings. Other than a few random and isolated single letters and numbers, the only legible marking left is "4/45".
This one differs from other Bofors SAP projectiles that I have seen as it has a flat top (this is original, not cut or filed) and has a more curved and streamlined appearance - like the HE projectile. Earlier SAPs have a tighter ogive radius, much like the 2 pdr AP. This one has a base plug fitted, so no tracer element. The dimensions are 40 x 154mm (just over 6-1/16") and the centre of the cannelure is 9.5mm (3/8") below the drive band. It is most likely Australian made, but as always, it will be to British specifications.

I only have a 1941 dated Bofors manual that describes the Mk 1 SAP projectile, but this is obviously a later mark. Does anyone have any details of this projectile, what mark it is, what it would have been filled with and if it was also available fitted with a tracer? I presume the colours were black with a white tip, but what filling bands were marked?

Thanks,

Graeme

 

[fert]

Hi,
I have a SAP 40mm similar yours i can not identify.
this one didn't have a base screw.
markings:

NX35/6240
40 M/M SAP
BS
TL
LOT
9/40

base:
B B or 3 B

anyone could help me to ID please?
thanks in advance
best regards

 

[Darkman]

Hi fert.

Your shell is virtually identical to mine except that it has a "pointier" nose - perhaps for a greater ballistic capability utilising a different propellant, or maybe just a different interpretation of the design? I can't tell if the base is threaed or not in your photo, but I presume it is. I don't know if these were (could be) fitted with a tracer or the base plug was just for filling.

The arrangement and details of the stamping indicates to me (but I am no expert) that this is a British/Commonwealth shell. The top line - NX35/6240 - maybe a drawing or design number. "BS" is for Bar Steel. I think that "TL" is the maker's code, but I don't know who that is. The absence of a Lot number may indicate that this shell was never filled or finished.

Regards, Graeme

 

[ozziammo]

Darkman,

Your projectile has a distinct 2pdr Vickers AA feel to it, maybe a prac or base fused HE?

The basic shape, driving band contour, distance from drive band to crimp groove & the couple of Ns that are stamped (typical Navy).

Has the base plug got anything stamped on it?

Regards Ozzi.

 

[Darkman]

Hi Ozzi.

I was not certain that this is a Bofors shell and that it may indeed be something else, such as a 2 pdr AA. But now that fert has posted his projectile that is very similar and it is stamped "40M/M SAP" I am reasonably sure that it is (but not 100% though). The different distance from the drive band to the cannelure groove compared to a normal Bofors shell is a bit of a worry though - but I think I have seen reference to this on the forum somewhere else?

The "Handbook on Ammunition 1945" is a Navy publication, and it makes no mention of this type of shell, SAP or otherwise, so I don't think it was a naval application. There are no markings on the base plug.

I am still open to ideas as to what it could be though.

Regards, Graeme

 

[Darkman]

Ozzi,

I just went and found an old 2 pdr Vickers shell and I'm afraid you may be right. The drive band profile on my "Bofors SAP" is more like the 2 pdr and does not have a flat section like the standard Bofors. Also the distance from the drive band to the groove is identical to the 2 pdr (3/8"). I have just had a closer look at the projectile fert posted and his has a more Bofors like driveband (large flat section) and the drive band to cannelure groove distance is much greater - so the projectiles are not alike at all. Maybe my shell is some type of 2 pdr Vickers. I don't know if the base plug on mine is just a transit plug or not, and it was fitted with a base fuze. Stumped. I found a picture of a 2 pdr Vickers HE shell that is similar. Regards, Graeme

 

[Darkman]

I am leaning towards the idea that my projectile is a 2 pdr Vickers practice shell. Looks like it may have to go to Ron H as I am mainly interested in Bofors stuff.