John my man i think martin does not have a jacket maker
for copper tubbing but rather a jacket maker for copper flat's becouse he has the hydro and multi swage press's
So he make's what little he can from copper flat strip's
somthing like this i hear tell



I also hear tell he buy his jacket's now from a good friend

name Butch but then again what do i know maybe he does have a tubing jacket maker hiddin some place i just have not been able to find it

The 3/8" L wall tubing is first formed into a cup, which is still 3/8" in diameter. It is then run through a draw die to reduce it to what ever caliber you want. If you want a .375 jacket you just reduce the size of the 3/8" cup you made to .371 or .372", drop in a core and swage it back up to .375". So by having a jacket making die set to work with 3/8" L wall tubing you can make jackets in .30, .323,.338, .358 and .375, by using the appropriate draw dies. I think Martin has a .50 cal jacket maker set to use 1/2" L wall. With it and the right draw dies he can make jackets for .416, .458,.510 and many others.