Again, please explain how you would clean a permanently attached can after shooting a corrosive powder? Simple answer is there is no good way to do it unless the can comes apart. The inside of that thing will be loaded with gunk and without a good fast way to dry it.

It's not approved for shooting a corrosive powder with it.
It's only approved for shooting BH 209 powder. (Page 7)

Page 63 of the Maxim .50 Instruction Manual PDF details the cleaning procedure that should be done every 50 - 60 shots.
It's a simple 2 step warm water and then hot water rinsing process while the barrel is kept in an upright position with complete air drying required afterward.

I suppose that after cleaning, hot air can be used to facilitate the drying process

https://silencerco.com/wp-content/th...nual-small.pdf

What makes you think BH209 fouling is not corrosive? It certainly is corrosive just not nearly as bad as most subs AND it should be cleaned with a oil based solvent not water based.
http://www.blackhorn209.com/specs/general-cleaning/
http://www.blackhorn209.com/faqs/
Thats gunna get rather pricey flushing a can with a solvent plus other issues that might occur from not being able to dry it easily. Would you just "rinse" your barrel out and call it good to go?...Somehow i doubt it. You would want to at least run a patch or brush to remove it.

I only used the word corrosive in response to your question about shooting corrosive powder through the can which I took to mean black powder or Pyrodex
that contain sulfur and produces sulfuric acid and other corrosives..
It's my understanding that moisture and the oxygen in it is what causes corrosion & oxidation

I really don't know anything about BH209, but since it's recommended to use an oil based solvent to clean it as you say, perhaps that's why they recommend warm and then hot water to
flush it out since the Maxim company must believe that it's at least partially effective.in flushing out some carbon deposits & particles that can absorb moisture or clog the baffles in the can.

Perhaps the metal in the can is made out of high quality rustless stainless, the kind that pots and pans are made out of, or another rustless aerospace metal?
And there may be cheap solvents that can also be used to help flush out the can, such as alcohols, cheap water based degreasers, water soluble cutting oil, natural citrus cleaners, Pine Sol, Mean Green or such.
There's even steam cleaning wands or pressure washers.
Spray it with some Fantastik and then take it to the do it yourself car wash... :-)
I'm just guessing because there must be a reason that Maxim recommends flushing it out so often with plain heated water..
If it's flushed out often enough, then perhaps the carbon residue never has much of a chance to accumulate to significantly interfere with its operation..

Since BH 209 is a nitro based powder, there's probably not any traditional creosote residue that would be produced as a by product as if it had contained charcoal as a fuel.
I wouldn't be too concerned about it since I don't plan on buying one.
I am trying to think of how I would thoroughly clean it if I owned one.
But they could have recommended another bulk solvent and cleaning procedure instead of simple water flushing if they thought that it was really necessary.
They could have designed the can with a built-in cleaning port
It may indeed have a special advanced design or materials that makes it so expensive.

Maybe the can will eventually get filled up with enough Black Horn goo to blow up the shooter? LOL!
Even though I thought that BH didn't create much goo to begin with...

You touched on 2 pretty good points but i still have an issue with it.
Alcohol to help dissipate the water and citrus cleaners might be somewhat effective. The detailed cleaning instructions say to leave it muzzle up when drying. The Strikefire they are using is not a stainless or nitride barrel and all that stuff still in the can is going to be draining into a more or less unprotected bore. Even oiling the bore before the drying process just does not seem like a great option. It just seems like there are too many negatives and too many hoops you need to jump through.