Dakotan. I agree with Reddog. The Berdan primers are of different sizes. Your customer can get a Berdan decapper from Huntingtons, and primers from the Old Western Scounger.
The decapper is $43.95, extra pins $3.95. There is a conversion to the primer seater at $19.98 and the seater assembly for the proper size primers is $11.10 Also a shell holder drilled for the Berdan primer at $17.50. These prices are from the Huntington 1999 catalog and should give you a general idea of costs. Apparently they don't carry Berdan primers.
You can reach them at (www.huntingtons.com)
I have no prices for the Old Western Scrounger, but you can reach him at:
The Old western scounger
12924 Hwy. A-12
Montague, CA 96064
Ph: 1(530) 459-5445.
Hope that helps.