Most larger banks can furnish Canadian pennies, and if you stay out of Canada (especially with some of your jackets on bullets) ... They are also slightly more copper than the old US Lincoln...
Copper tubing. Mr. Corbin, Dave (has a brother Richard, not near as talkative) has books that go over this in detail and you can download pictureless copies free from swage.com... Any machinist can make you dies to "end round" tubing and make jackets, but it won't be cheap. Mr. Corbin, Dave has sets, often on the shelf, to do this. AND with the inconsistant tubing available today, furnishes consistant tubing...
And Mr. Corbin, Dave furnishes die sets to make jacket discs out of copper strip and jackets out of the disks, and ... just bring money. It ain't free... LUCK.