I hope that’s a smooth-bore musket. If the barrel is rifled it is obviously a sniper’s weapon. Only fedgov officials may use weapons with rifled barrels...
This was actually british law prior to the first American Revolution. Here they come again.
Oh, no doubt. But, just looking at the image a second time, they don't have to just ban the rifle. In California, blackpowder is restricted to one pound limit at purchase... providing you're willing to drive to one of the few gun stores that will bother to stock and sell it. Lead to run your own roundballs is getting scarce, let alone more expensive to purchase in ingots. Lead has become a restricted or banned substance altogether in many places. The EPA shut down or is shutting down lead smelting and tanneries. So, shooting bags, accouterments and other whatnots will likely dry up or be far too expensive or unobtainable for even the most die-hard enthusiast.
So, we know all the materials and components of all firearms and shooting sports are being restricted or banned too.