has it about right for the traditional style of muzzle loader.
Modern guns need some burnishing and pit filling. Smoke poles work entirely different when looking at bullet surface and barrel interface. Lead and iron is a whole lot different then copper and steel. There is no burnishing and no pit filling with the lead.
Now if you are using sabots and pyrodex type powder.....weeelllllll, now you have a modern rifle with modern bullet speeds, modern copper (or something close to it) rubbing on modern steel, and modern propellant. Things are a lot different. That version will require shooting in. About like you would with a modern rifle.
Not meaning to sound too much like a smart alec - but it is true about how you treat your barrel. Lead balls with cloth patches fired down barrels with very slow twist barrels (66 to 72)are really different then hard copper coated bullets with pretty skirts fired down barrels with fast twist rifling (26 - 36).
With modern steel that muzzle loader barrels are made of today, 'seasoning' is pretty much a misnomer.
Read this and make up your own mind.
Once in a while, the topic of "seasoning a barrel" comes up. Anyone with a basic understanding of modern steels realizes that they are non-porous compared to a cast-iron skillet, and they cannot be seasoned one way or another. One can long for the return of primitive metallurgy and the return of Damascus barrels with porous welds on twisted steel, but I'm not one of them. Your local Ryerson's can educate you on the properties of modern steels, if you have any real interest.
The subject of corrosivity comes up from time to time, and as far as I'm concerned all of these propellants are corrosive, though markedly less so than blackpowder or Pyrodex. Sulfur salts have long been the main culprit.
The ascorbic acid based propellants aggressively attack and corrode brass. My impression is that they are somewhat less corrosive than Triple Se7en to barrels, but I'm not willing to intentionally ruin any rifle barrels to find out. The gluconic acid salts and alkali metal nitrobenzoate salt based Triple Se7en, with some carbon added to give it a little color, remains the best available solution for today's modern muzzleloaders that cannot use superior, non-corrosive, smokeless propellants.