Antiques and NY-gun law
New York's current code defines a firearm in NYCL PEN 265.00. It includes (emphasis mine):
- "Firearm" means (a) any pistol or revolver; or (b) a shotgun having
one or more barrels less than eighteen inches in length; or (c) a rifle
having one or more barrels less than sixteen inches in length; or (d)
any weapon made from a shotgun or rifle whether by alteration,
modification, or otherwise if such weapon as altered, modified, or
otherwise has an overall length of less than twenty-six inches; or (e)
an assault weapon. For the purpose of this subdivision the length of the
barrel on a shotgun or rifle shall be determined by measuring the
distance between the muzzle and the face of the bolt, breech, or
breechlock when closed and when the shotgun or rifle is cocked; the
overall length of a weapon made from a shotgun or rifle is the distance
between the extreme ends of the weapon measured along a line parallel to
the center line of the bore. Firearm does not include an antique
- "Antique firearm" means:
Any unloaded muzzle loading pistol or revolver with a matchlock,
flintlock, percussion cap, or similar type of ignition system, or a
pistol or revolver which uses fixed cartridges which are no longer
available in the ordinary channels of commercial trade.
So, under NY Law, a gun is only an antique if unloaded. Loading it makes it apparently no longer an antique, but a (normal) black powder firearm, with the normal firearms rules applying to carrying, transporting, and using them for legal or recreational purposes - which for NYC would mandate a registration since 1977 and in 2010 would have required license-to-carry.
Opinions of the State Attorney General:P: "December 19, 1977 (informal No. 77- 00): Unloaded replica muzzle loading percussion pistols may be sold, purchased and possessed without a license. Simultaneous possession of these pistols and the necessary ammunition to discharge them requires a license. PL 265.00 (14) & (15).
According to FindLaw, the last revision of the section was in 1999 and did not include changes to sections 3 and 14, so they can be presumed to have been the same in 2010, and indeed, the alleged 1977 quote fits that. So as a result: you can have it, but not be able to load it or you need a firearms registration/license. The only time "Black Powder" is used in the Penal code section is when they speak of Criminal Possession (S265.01), which specifically lists almost all possible firearms in (4), separating black powder weapons from antiques (which after all are unloaded only!):
possesses a rifle, shotgun, antique firearm, black powder
rifle, black powder shotgun, or any muzzle-loading firearm,
But you might also need another license for the acquisition of black powder as it is an explosive (in quantities above 5 lbs) and you have to abide by special regulatiosn. However, in a practical manner, it seems that the supply of black powder might be rather limited in NY and sometimes close to impossible without a license for explosives - at least that's what some half-hour of reading muzzleloader boards told me, but legally you could buy less than 5 lbs without a license as that would be not an explosive under the law.
[NYCL LAB]§451 Definitions
- "Explosives" means gunpowder, powders used for blasting, [...], smokeless powder, [...] but shall not include [...] quantities of black powder not exceeding five pounds for use in firing antique firearms or artifacts or replicas thereof.
§458 Liceses & Certifications
[You need a license to buy, handle or use any explosives as defined above]
- Except for the Provisions of subsection 11 [banning sale of explosives to minors] of this section, this shall not apply to smokeless powder
12 NYCRR 39.2 Definitions
(n) low explosives [...] for example, black powder
Antiques and gun forensics
Often, antiques and forensics are tricky: Antiques, especially non-rifled antiques that use a greased patch around roundball, do not leave easily identifiable rifling on the bullet, just like a smoothbore shotgun does not mark its grapeshot or slugs.
Not an answer for 2010 NYC but germany
Firearms law is a federal matter in Germany, and it has decided that even new, fireable replicas of Percussion, Flintlock, and Matchlock guns are generally free to be sold to people above 18. On the other hand, you can't fire them without black powder, and that requires you to acquire a powder handling license to obtain the powder and be allowed to create the charges.
Provided you have such a gun that requires powder and go to a shooting range, where one of the shooters has the license, he can weigh and prepare the powder tubes (you are not allowed to charge a gun from a powder bottle/flask that contains more than one charge of powder) or paper cartridges, then you can shoot it, even without a black powder handling license or a "Waffenbesitzkarte" (Gun license). But if you want to prepare the charges/paper cartridges yourself, you need that license. And afaik you need to be a gunsmith to make a gun yourself. And shooting ranges are required to require that you have "Beschuss" on your black powder weapons (proof test). The correct proof mark is Eagle over SP for "schwarzpulver". You would be technically allowed to get an Eagle over N (for Nitrocellulose) and shoot with black powder, but you are not allowed to load nitro into an SP. And you can't shoot projectiles from an Eagle over B as those are "Böller". The proof is meant to guarantee the safety of the device.