I agree with rebel: You don't season a steel anything.
Seasoning is something done with iron impliments, such as cast iron frying pans. You burn oil or grease into the surface to fill the pores.
Before the Industrial Revolution of the 19th century gave us reliable steels, all barrels were made of one form of iron or another. As a kid, I was shown a iron barrel squirrel rifle that was so soft, you could literally mark the barrel with your fingernail. The barrel on that rifle was about 3 inches cross, 3 feet, long, with a bore of about .32 caliber. I wish I had that gun today, so It could be restored. It would be a kick to shoot it. It weighed more than 30 lbs!
Since the American Civil War, barrels have been pretty well made of steels, and not iron. People will read an old history of colonial times, where they talk about seasoning a barrel, and all of a sudden, they have " discovered " an old " secret " for making a gun shoot better. It just won't happen in a steel barrel.
I once talked Homer Dangler into having one of his barrels Chrome plated, to see if it would improve accuracy, or cleaning, or anything. He reported that there was no measureable improvement in accuracy, but the gun was sure easy to clean! Nothing seemed to " stick " to the inside of that barrel. ( Chrome plating fills the pores of the steel with Chromium, and trace alloys, preventing powder residue from sticking to the barrel. You still get crud, but a slightly dampened patch( with spit in good weather, alcohol in below freezing conditions) is all that's need to clean out the barrel. A chrome barrel may be one where all you need will be a good lubed patch around the next bore to keep the gun " one shot dirty ", in most weather conditions.