Trying to determine which tube (OD/ID) size would work with the 1.355 cones. I have been sick so it's probably why my brain is refusing to do the math. More than likely will go with a DM titanium tube. Planning to use for 5.56/300BLKOUT.

1.5" Ti usually will have a wall thk of .07
1.5 - .07*2 = 1.36

So the 1.500x1.375 version sounds correct. (at least those are the options under the Premium Titanium Tubes over at DM)

You will want the 1.360 Id for 1.355 cones. The 1.375 Id tube will require the 1.372 od  cones

Gotcha. Appears the only option for that size is under DM's Select Titanium Tube. Will go with that. Thanks!

EDIT: Spoke to a buddy on here and he said not to go with the ZmachineWorkX cones (which is my limiting factor here) and contact Randyand for his custom cones. Which I have done.

ZmachineWorkX cones no good??

ZmachineworX provides quality 60° and radial.cones. I have built several cans using his cones. The same cnc shop that makes the cones for ZmachineworX also makes cones for DM..

The main difference is ZmachineworX uses a full skirted cone and DM uses a .125 skirt. To get the optimum spacing I was  cutting the skirts off the ZmachineWorX cones to get what I wanted on the skirt length. Then adding back the interlock lip. This is one of many things I changed when the RSC was released, no skirts, which makes for a lighter can since spacer material has a thinner wall and makes better use of the can volume.

Good to know and thanks for the information!