Pinfire case identification

This was found in the cylinder of an antique Lefaucheux pinfire revolver. What is it ?

It has no base. I thought maybe it is a case separation failure, but the separation line looks straight and even, almost like it was made that way. Were any cases made from a separate base and tube ?

The pin hole is not fully open at the rear, so it is not a calibre reducing sleeve.

The length is greater than a normal 11/12mm pinfire revolver cartridge. Is it a carbine length case ?

Outside diameter = 11.9mm
Outside neck diameter = 11.5mm
Inside diameter at base = 10.6mm
Inside neck diameter = 10.4mm
Overall length = 22.8mm
diameter of pin hole = 2mm
Material appears to be brass.

I forgot to say, the neck has a crimp which is visible in some of the pictures.

You pretty much described the exact dimensions of the 12mm carbine length pinfire by Houllier-Blanchard.

It came in this box:

It was made between 1855 and 1872 by Houllier-Blanchard in Paris, France. These cartridges are the longer size that were popular with the revolving carbines used in the US Civil War, as well as other countries.

Hello Aaron

First it is impossible to see from which manufacturer is a pf case coming from when you don’t have the base.

Second, Houillier Blanchard never manufactured any pf ctge.

He registered patents for special pf ctges, but nobody has ever seen one.

The ctges with his hstp were manufactured either by Chaudun or by Gevelot.
(Furthermore the box you show looks like very much as a Gevelot one)

12 mm long PF were manufactured in Europe by many companies


Thank you gentlemen for your replies.

The case body pictured in my post I think has had the base cut off. Looking at it with a loupe it looks like there are cut or file marks across the end of the tube, not something I would expect from a case separation.
Why this was done, and why the body was left in the revolver cylinder has me baffled.