The extractor for the .310 Martini Cadet broke. I have tried 'Gun Parts,' several sources in the USA, and one in Australia, without success. I converted it to a .218 Mashburn Bee 10 years ago, and have used it on ground squirrels here in Montana with much pleasure-to me at least!

I copied the following Martini Resource List over on Rimfirecentral. Lots of places to check, but IIRC, extractors are tough to find, and expensive when you do find one.
http://www.rimfirecentral.com/forums/showthread.php?t=76209
Don

Try the guy who runs this site:
Martini Gallery