[mconn1]

Slipknot,

I just tried your method of creating a "gun barrel".

It worked splendidly for me. No left over surfaces or vertices. No messy boolean leftovers either. All this from 2-10 sided cylinders.

I did have to make the final object 2-sided in order for all of the surface lines to show up properly in wireframe.

Things I did to make sure there are no artifacts:
1. Made the inside cylinder longer than the outside cylinder.
2. Made sure all of the end caps of the cylinders matched according to the end cap surface lines.
3. I think the outside cylinder was first in the hierarchy.

Not sure if this actually helps...Just trying to replicate what you did.

Just tried to use the Boolean subtract on another set of cylinders. I combined each end cap of the cylinders. I ended up with a lot of Boolean artifacts on the end caps. I hope you didn't combine your end caps because you are not dealing with simple triangles. The complex surfaces are not handled very well with the Boolean commands.

Just tried another strange set of objects. I made 1 large triangular cylinder and placed 3 10 sided cylinders inside. Boolean subtracted each of the 10 sided cylinders from the triangular cylinder, not as a group...but one at a time. No Boolean artifacts showed up. It was actually a nice looking object after all was said and done.