I've been shooting & building muzzleloaders since 1977. I've been shooting inlines (blued & stainless) since the early 90s. No soap and water is needed (ever) with either type. Tepid water, Windex, or windshield washer fluid works perfectly. Barrel removal is ok for Hawken breeched type muzzleloaders. It's dumb with any other type.
I've been doing it my way for many many years. I can have my guns spotless in 15 minutes. You can waste your time with old school (supposedly traditional) methods if you like. I don't have any to waste.
IF you ever shoot that MK-85 with Black Powder or Pyrodex, you will see what I am talking about. The blowback fouling WILL migrate down into the trigger, between the action/barrel and stock. After that happens, its only a matter of a couple days and your stainless will have pits in it. I have seen the results of what happens when the stock is not removed for cleaning, not my rifles, but others.
I am not saying you have to clean with soap and water, your Windex will clean it, but it can't clean what it can't get to. If you think you can clean a MK-85 without removing the stock, you WILL have corrosion between the stock and action, guaranteed. Just running a few Windex patches down the bore isn't going to cut it. Like I said, good luck!