11x59R Gras cartridges/brass
Forget OWS (just a brand name now, owned by someone else, and still carrying the opprobium from the last ten years of trading under its independant status.
If you want ready to load brass, Buffalo Arms is your supplier.
If you want to make your own ( a bit short at 56/57mm, but of no consequence with BP/Light Smokeless Loads)) Get .348 Winchester brass, make a taper expander to get the Neck out to about .45 calibre, neck size to hold a .446 Bullet (Lyman or Lee ".43 Mauser" Moulds are ideal), Load and fire-form.
I do this regularly with commercial quantities here in Australia (I just expand, then Full length size...and allow the user to fire-form.
Some rifles do require a slight bevel on the case rim, but most Gras rifles I have found are "lax" enough to close on a .348 rim thickness without bevelling.
The other method (if you have sufficent quantity) of 8x56/60R Kropatschek Blank cases, is to Pull them down, remove the cotton over-powder wad, just use a little Wax Plug (very little) and fire form...messy, and the original cases are Berdan (RWS #6504), but the brass is good (I only had a 15% split rate)...then anneal, and reload.( one can also use CBC 6,45 shotgun Berdan primers)
Again, the "blanks" vary from 56 to 60mm lin length, and may need some trimming.
Underlength cases are not a hassle in BP rifles.
Good luck,
Doc AV
AV Ballistics.