The second amendment does not say anything about your parking lot, your private property, or federal property for that matter.
The right to own weapons is the right to be free.
If you don't like free men on your property, you have a perfect right to refuse admission to them.
That would include all citizens of the USA.
Perhaps that would cut down on your business, having no employees, no customers.
My right to life does not end at the borders of your business. My right to keep and bear arms is just as absolute.
So sorry, but that is the way it is.
And they are free to either enter on my terms, or not...by having the freedom of choice, we are both free.
On the other hand, if the government enjoins me to accept men with guns on my property, against my wishes, then government has usurped my freedom without asserting yours because yours was never in danger of being usuroed by me via your choice to either enter or not enter my property under my terms.
Your right to keep and near arms exists solely for the purpose of defending your property...that includes your life.
When you assist in violating the most basic of all individual rights, the right to what is yours, you effectively negin negating all other rights. You may not violate one unalienable right in the name of another.
Life, Liberty, and Property
The right to life is essential to a free society. Without this most fundamental of human rights, still denied to millions of people the world over, the state is no longer a protector but an oppressor. Obviously, early Americans envisioned circumstances in which there could be a justified taking of life, such as capital punishment, but no one was to "be deprived of life...without due process of law."
Liberty is simply the freedom to act as one will to seek fortune or pleasure or contentment. Government control over the activities, wealth, education, dwelling, career, or any other part of human life is a constraint on liberty. Early Americans saw that certain governmental functions were set forth in Scripture, and thus not all state coercion would be a deprivation of a biblically conceived liberty. Modern American society, however, has expanded the role of government far beyond its biblical limits, such that the liberty the framers envisioned for U.S. citizens has been lost.
Fundamental to a free society is the basic right of property. Though this right is routinely trammeled today, to the framers it was inconceivable that this right would not exist in a free nation. Wrote John Adams,
Property is surely a right of mankind as really as liberty.... The moment, the idea is admitted into society, that property is not as sacred as the laws of God and that there is not a force of law and public justice to protect it, anarchy and tyranny commence. If Thou Shalt Not Covet , and Thou Shalt Not Steal, were not commandments of Heaven, they must be made inviolable precepts in every society, before it can be civilized or made free.1
Without the right of private property, a society will not grow and prosper. If the government will not stop my neighbor from taking what I have produced, I will not bother to produce. Not only are incentives corrupted, but the economy turns into chaos. Early in the 20th century, the Austrian economist Ludwig von Mises pointed out that an economy without private property and a free-market price system will fail for lack of information about how to allocate resources. An economic system with few or nonexistent private property rights will collapse just as the Soviet Union did a decade ago. -- Source
What does the Constitution do?
Does it "grant" rights?
Or does it impose limitations on the government's ability to encroach on already existing rights?
The latter of course.
The Constitution does not have to mention my rights for me to have those rights.