Wisconsin does not require registration of handguns. Information for you:
http://crime.about.com/od/gunlawsbystate/a/gunlaws_wi.htm
MOST states do not require registration of firearms.
I know of no gun registeration in Maryland. No such thing as a unregistered gun.
in MOST of the US, there is no requirement to register a gun.
There is no Federal law requiring registration of guns. MOST states also do not require it. No penalty.
PA doesn't require registration ofordinary Title I firearms, to include handguns.
Not worth 3+ years in jail move to VT
As long as you legally possess the gun, none. Texas does not require registration of ordinary Title I firearms.
There is no law requiring registration of ordinary firearms in Illinois. The possessor must have a State Firearm Owner's ID Card.
No
There is no general requirement to register guns in Virginia. Only a few states in the United States require guns to be registered; some states have made it illegal to register guns, as the United States has made it illegal to create a national gun registry.
Depends on the law where you are, and whether it is legal to have a gun, and what you were doing with it. Without that information, we cannot even guess at an answer. Sort of like "what is penalty of having car?"
The only form of penalty is possibly having to pay the defendant's court costs if you lose.
Being sent to jail is the most serious penalty for not having a Visa. However, before jail time, typically, a person without a Visa is just fined.