British Nitro Express calibres question

Here are 2 British Nitro Express cases I acquired earlier:

What are the correct calibre (case length) designations?

The first one is .500 calibre and has an OAL of 2.375in. Headstamp is “C KYNOCH C .500”

The second one is .400 calibre and has an OAL of 2.37in. Headstamp is “KYNOCH .450-400”

The answer to this is probably simple.

Any ideas?


The 450/400 is called the 2 3/8" case. I don’t know about the 500 but a SWAG would be that it, too, is the 2 3/8" case.


the .500 full nitro case (CC) was offered in 2 sizes; 3 inch, and 3 1/4inch.
So someone took a saw/ file to that one. From the photo the mouth of the other looks a little ragged? or belled? If you look carefully at a cut-down case you can see, as its usually not square with the vertical line somewhere as you rotate the case. Also get out your lupe & look for tool marks.

Unfortunately the neck does look like someone has cut the case down, which is a shame, as it is a nice early Nitro headstamp.

Can’t be it a 500 BPE instead of 500 NE?If it is a 500 BPE it is apossible case lenght.The second one is a 450/400 NE wich corresponds to the swiss 10.3 X 60R


The .500 Looks to have been sawn down, and it has an early Nitro headstamp (2 Cs at 3 and 6 o’clock), which indicates the round was loaded with cordite smokeless powder, so as far as I know it cannot be a .500 Black Powder express.