6pr 7cwt case with unusual stencil ?

[Gspragge]

I picked up this typical common 6pr 7cwt case this weekend.
I didn't pay much attention to it until this evening. The headstamp is the usual
but I have never come across the stenciled black band around the base and the letters HV in two places.
I presume this means High Velocity, so a non standard load ? or for the Disgarding Sabot projectile ?
The base was thick with green and plaster bits oddly -

 

[ThomasP]

There were two different charges for the standard 6.291 lb AP projectile.

The original charge gave a MV of ~2650 ft/sec when fired out of the 43 caliber barrel, while the HV load gave a MV of ~2800 ft/sec.

The original charge gave a MV of ~2800 ft/sec when fired out of the 50 caliber barrel, while the HV load gave a MV of ~2950 ft/sec.

 

[Gspragge]

Thanks for that I had no idea ! Here is another one, more complete.

 

[ThomasP]

Nice cases. I had not seen an actual HV marked case before, only illustrations

Oops! Just noticed I made a typo in my post above. The standard 6pdr 7cwt AP projectile weighed 6.281 lbs (not 6.291 lbs).

Sigh, I am going to have to start wearing reading glasses in the future.

 

[SG500]

Nice case. If it was for the discarding sabot projectile the crimping groove would be right at the top of the case, just a few mm from the mouth of the case. If the crimping groove is further down the neck of the case then its for one of the other loadings.

Dave.