I was going to bring up the same concerns as c-fbmi did above. I'm another that worked in radio and other electronics their whole working life.
Basically if it helps your metal barrel will act like the secondary winding of a transformer that is shorted out. So a lot of the power that SHOULD go into the emf currents and counter magnetic field from the projectile itself will be absorbed by the metal of the barrel. What you need is a barrel bore that is totally non conductive as well as being non magnetic.
If you're hoping to use off the shelf bullets be sure that they are made with a heavy copper jacket. The thin plated over lead bullets won't have enough current capacity in the thin jackets and you'll get less back EMF and thus less back magnetism.
In the end you may find that you're better off to work with some of the heavy copper jackets with the lead removed so it looks sort of like a hollow back pointed front bucket. The hollow shape will provide a fin like stability without the need for spin from rifling. That would let you get away with a non metallic tube of some form. Perhaps something ceramic?
Basically if it helps your metal barrel will act like the secondary winding of a transformer that is shorted out. So a lot of the power that SHOULD go into the emf currents and counter magnetic field from the projectile itself will be absorbed by the metal of the barrel. What you need is a barrel bore that is totally non conductive as well as being non magnetic.
If you're hoping to use off the shelf bullets be sure that they are made with a heavy copper jacket. The thin plated over lead bullets won't have enough current capacity in the thin jackets and you'll get less back EMF and thus less back magnetism.
In the end you may find that you're better off to work with some of the heavy copper jackets with the lead removed so it looks sort of like a hollow back pointed front bucket. The hollow shape will provide a fin like stability without the need for spin from rifling. That would let you get away with a non metallic tube of some form. Perhaps something ceramic?