SilencerCo released the integrally suppressed muzzleloader. Since it is considered to be an antique firearms, it doesn't require NFA stamps and paperworks.
It can be shipped to buyers in almost every state without need to go through FFL, except in Illinois, New Jersey, New York City, and Washington D.C.
There has been some questions on legality depending on locality such as California and New Jersey.
Retail price is $999
https://www.store.silencerco.com/collections/maxim-50
Loading Tube is $8 and cleaning patches are $9