imported post
From what I've read a firearm must be manufactured before 1898 for it to be an antique. Not just designed before 1898, but if I recall correctly either the stock or receiver, I can't remember which it is, (And I guess the frame if it's a handgun?) of the specific gun in your posession has to actually have been manufactured before that time and somehow identified via markings as such.
Of course, it seems to me that it is still considered a firearm. Thus even if you could legally purchase it below age 18 and without a permit or background check, I still don't think you can legally carry it at this time. I also don't know that you can legally purchase it below 18. I think the only real difference with an antique is just that for anyone 18 or over, they don't need a background check in a store or an FFL to do the transfer when ordering one online. It can just come straight to their house.
I think you should consider purchasing a mixture of CS tear gas and OC pepper spray (Sabre makes them), and a quality pocket knife. The pocket 3/4oz unit has a capacity of about 30 one second bursts (Stream type) and a range of 8 to 10 feet. I suggest this regardless of whether or not you're able to carry the firearm because having a single shot muzzle loader could present a major problem. If you miss with that gun, you're then going to be dealing with a lethal force encounter unarmed. If you have multiple attackers, even if you score a direct hit on one of them you may still have a problem. I do not recommend carrying such a weapon for defense, ever. If they have a gun, you're probably going to loose. If you blind them through immense tear production in their eyes initially, they will have a much harder time shooting you. This will allow an easier escape on your part.
I do hear people say, "that wont stop somebody on x, y or z drug." Unfortunately these folks have probably never done x, y or z drug and have no clue what they're talking about, or they're selling a taser and want you to buy their product. I also fail to see how the tear production would be negated by drug use. They will cry regardless. It may not hurt as badly if they were on some kind of pain killer (And meth is NOT one), but it will still cause them to tear up and have trouble seeing as well.
A taser, while it can be a good defensive tool, will only incapacitate during the application of current. If they're truly determined, after you stop "tasing" they may still come at you. The spray will not stop having its effect when you let go of the "trigger." Not to say a taser is a bad idea or ineffective, but I do think people give it a bit too much credit compared to a good spray. There's a reason why police sometimes "tase" people repeatedly. You also have to apply it to one target until they stop. With the spray you can hit one target and move on to the next without having to continue to go back and spray the first one.
None of these items offer a guaranteed result, but personally I think that what you're doing with the muzzle loader may be a very bad idea. Below are two items you might want to consider acquiring (Or something similar).
Sabre 3-in-1 3/4oz Pocket Spray (Can't beat it for $8!!):
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=664996
Ka-Bar Dozier Folding Hunter ($19 knife, very high quality, light weight and good design. For the money it's hard to beat.):
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=318864&t=11082005
Welcome to the forums btw.
Edit: It was 1898, not 1895, and it includes replicas.
Still, I wouldn't recommend carrying these types of weapons for defense purposes, even if it were legal.