I bought up an assortment of brass in order to get some that I needed. Included with this assortment were some extras that I cannot use. I will ship them to whom ever wants them free of charge and only ask you make a good-will donation to the Forums.
Note: This is all Berdan primed and is currently primed brass.
Qty 9-6.5x53R, Kynoch marked "6.5 m/m"
Qty 2-6.5x54, Kynoch marked "6.5 m/m MS"
Qty 3-6.5x54, PS marked "6.5x54"
Qty 3-6.5x57 Mauser?, Kynoch marked "6.5 mm M"
The 6.5x57 is as close as I can get with measurements. The case is a bit longer than the spec but the rest seems plausibly close.
I don't have any history on this brass. It looks to be in good shape but used.
PM me with an address and I'll get it out to you in a few days.