Advocate:
You can do almost anything with the right equipment. The Corbin website is an excellent source of info (
www.corbins.com) as is the series of books he sells. His brother at
www.rceco.com also has a lot of info on line.
Corbin sells a core bonding flux you can use to make bonded bullets, and he has a procedure for making a partition-type bullet - this entails the insertion of a smaller jacketed core backwards in the base of a bullet.
Unfortunately, it is very difficult (and - when possible - expensive) to obtain commercial jackets over .30 calibre, so Corbin sells kits to make jackets out of tubing. This results in thick (though soft due to annealing) copper jackets. Butch Hairfield who I mention in my initial post is starting up a jacket business, and offers .35 calibre jackets in 3 thicknesses .030 (similar to tubing jacket thickness), .018 and another that I can't recall right now, but it is thinner than .018.
If you use different thicknesses of jackets, you will need additional core seating punches. Possibly you may need additional core swaging dies and punches, and you may have to use different wire diameters.
Rick