Before anyone tries to argue if the 2A covers bullet capacity, let me introduce you to the chambers gun
This isn’t the gotcha you think it is. The only thing the 2nd amendment covers is “A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.”
Your argument that bullet capacity is covered is as valid as another’s argument that it’s not because it’s not explicitly stated, so it’s left to interpretation.
This law is dumb and doesn’t seem likely to actually do anything to curb gun violence.
However, if someone would like to own a Chambers gun or any other firearm that existed in 1791 when the amendment was ratified then they should be allowed to without restriction, including felons, children, people with mental health issues, illegal drug users etc. This is what the 2nd amendment guarantees in context
That context is important though. 230 years ago the most common weapons owned and available to the people were muskets and flintlock pistols. Single shot, muzzle loading weapons.
Let’s also not forget that James Madison redrafted the Second Amendment into its current form "for the specific purpose of assuring the Southern states, and particularly his constituents in Virginia, that the federal government would not undermine their security against slave insurrection by disarming the militia.”
It is incredibly easy in modern times in the US to be able to access firearms capable of dealing significantly greater death and harm than in 1791. It’s fair to argue that, in current context, the intent of the 2nd amendment would not protect magazine capacity. In fact the case that defined bearable arms, District of Columbia v. Heller, leaves much to debate about whether a magazine constitutes a “bearable arm”.