yes.
Think of a slug of stock cut to a short length.
A hole is drilled through it centrally.
Heated, a ram pushes it down through dies.
They start out small, and are drawn to length, stretching the grain structure longitudinally.
This is modern tube making for monoblocking.
In the cylinder video, imagine placing black dots on the slug, and then where they end up at, and what they look like when the cylinder is finished.
There are manufacturers that use "deep hole drilling" and some that actually hog barrels sets out of solid in their entirety.
Here's a Sabatti barrel making video, it's in Italian, but you can see bar stock, blanks, initial boring, and drawing of the slug into a barrel tube. Stretching those metal grains all in one direction for firearms use. Other use different drawing techniques.
https://www.youtube.com/watch?v=BttSSUYjpCg
