WVFred,

I just remembered that some months ago, Cabelas had a very unusual Mahillon double rifle in 500 Jeffery on their website for sale at one of their "gun libraries." It isn't there any longer and was probably sold but I wonder if they would be able to give you any information about pricing.

I have checked and learned that La Maison du Chasseur do have Mahillon records and they should be able to help you if you contact them.

Best wishes and do let us know what information you collect. Good hunting!