360 NE 21/4 or 9,3x57R/360 are the most likely culprits.

Ross Seyfried wrote a very good piece on them and the 38-55 in Handloader no.225 October 2003 called "Miniature Black Powder Express Cartridge"
Handloader October 2003

Go buy it if you don't have it - I think you'll enjoy it! There's loads, history and some really nice guns!

Cheers
K9_75

Last edited by K9_75; 06/07/10. Reason: forgot...
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"one does not hunt in order to kill; on the contrary, one kills in order to have hunted."

Jose Ortega y Gasset. "Meditations on Hunting".