The NRA site is not perfect, but it will give you a good idea about the laws. In short, you do not have to register your rifles or handguns since Md does not have registration of handguns. They do however keep a record of handguns purchased within the state. What they call "assault pistols", like semi auto uzis and calico pistols, you
cannot have at all . The exception to this is if the "assault pistols" are registered as NFA short barreled rifles and then the state may (or may not) ask for a $5 tax stamp every year like they do for full auto.
Big piece of advice I am going to give you here is that, since Md has a greater than 20 round magazine ban, buy all of the high capacity magazines you can for your guns
before you move to Md. There is no law banning possession of the magazines, just the sale, manufacter and purchase. I can drive 20 minutes over the state line, buy a 100 round magazine and return to Md without breaking the law.
When you transport your handgun within the state you have to have it unloaded and in a holster that can snap it in (a box with a latch works as well). Many places on the web erroniously state that you must have the ammo in the trunk or the ammo in the car and the gun in the trunk. There is no mention of this in the Md laws that I have ever found when reading them (but I am not a lawyer). You may want to do this anyway to avoid a confrontation with an unknowledgible cop (but I keep my gun in the holster in the front of the car next to a seperate loaded mag all the time without a worry when going to the range).
When you have your gun in your car or when you are carrying your unloaded gun in its snapped holster in public, you
must be on your way to the gunsmith, to the range, between residences (yours or others as the way I understand it), to a place of work and to a firearms transaction. I have heard, but it does not make sense, is that you cannot stop at a gas station or a store (to buy ammo for instance) while taking your gun to the range. (doesn't make sense because county sherrifs are subject to the same restrictions when going to and from work, and they stop all the time).
CCW all depends on your profession in Md. If you are a criminal attorney, a doctor, have to carry or transport money for your profession, or some other profession simlar, the sate
may issue . For the average joe, you have to have had been threatened and they make you provide 2 witnesses and a police report (IIRC).
Despite what you may hear, if you are not a felon, you
do not have to get a permit to wear body armor.
From what I have gathered about the law and since I have seen nothing to contradict my view of it, you can wear openly or concealed while on your own property, without restrictions.
And finally, there is a brand new forum site for Maryland gun owners that started about a week and a half ago and you can ask there as well.
www.mdshooters.com