2 PR No 3 Sub-Cal case

[Quatermass]

Picked this up a while ago, the headstamp intrigued me, 2 PR No 3, otherwise its a standard looking 40x107R Sub Cal case.
Do any members have an more info on the case, were purpose made cases marked No 3 rather than the SUB-CAL & H.A. MK II GUN. as seen on the converted cases?
Any information appreciated.

 

[Hoeksel]

I also have the normal case as you mention, with the additional stamp "for Mk3 only". All these cases have a half rimmed rim (how to say in correct English?).

 

[Burney Davis]

I also have the normal case as you mention, with the additional stamp "for Mk3 only". All these cases have a half rimmed rim (how to say in correct English?).

A half milled rim is the term you are looking for.

 

[tigbrand]

Hi Q, I think you are correct, the previously marked cases are earlier and state the usage of the case, these being the mk 2 training weapon and the in barrel sub calibre device used in large calibre naval guns. The No 3 relates specifically to the case. This would I imagine prevent confusion in service. Just my thought!

 

[Depotman]

I recall reading that the half-milled rim being used so that the sub-calibre round could easily be identified by touch at night. Depotman

 

[Tony Williams]

Interesting, I didn't know about the No.3 designation.

There were two 2pdr sub-cal guns, one used the full-sized 158mm case (for low-angle guns) the short 107mm case ammo was used in high-angle guns (hence HA). Both sub-cal guns were modified in WW2 for use in small naval craft: they were given breech mechanisms and mountings. See: http://quarryhs.co.uk/37-40mm.htm for more info.

 

[Quatermass]

Thanks for the replies.
I have a 1944 dated converted 40x107R case marked SC HA MK II GUN interestingly the word Sub-Cal has been dropped by this time and replaced with SC.
The question I have is if a newly produced case in 1940 was marked 2 PR No 3 why not the converted case(s) produced after this date?
Could the No 3 case be specifically for the guns on the small auxiliaries, a different loading from the Sub-Cals rounds?