Ed, things are a bit easier today.

The big job is gundrilling. I turned my Hardinge CHNC into a gun drill
with the use of a car wash high pressure pump and a special fixture to
hold the gun drill.

Push rifling buttons are available on eBay for about $200. I used my
30 ton hydraulic press with an air driven enerpac to push the button
right through.

I made a few just to prove I can.

Still, Green Mountain sells barrel blanks VERY inexpensively. This is
by far the best way to go for the home weapons builder.

Karl