First, we must accept that that the purpose of the Second Amendment and the entire Bill of Rights is so people can protect themselves from a potentially hostile future government. There is nothing else that guarantees the continuation of the Republic. People need to be well armed so that Government forces will respect and fear them.
Second, we must accept that millions of Americans are already armed with the sort of firearms that some would wish to ban. You can not disarm American Citizens without a fight to the death (AKA: Civil War). Banning any types of firearms going forward would only stop a minority of Americans from owning them. By doing so… you are creating a two class society, one armed and one unarmed. Medieval Society was divided up in a similar way. The Nobles being armed and the peasants being unarmed. Guess who ruled who?
In any Society, armed people will always rule unarmed people. In colonial America, all free men were armed, and this is the reason why we became a Republic. No one faction was able to gain an advantage over another faction… because everyone was armed. Hence everyone armed was equal. That is the birth of Democracy in America.
The continuation of a Democracy hinges on the expansion of the greatest number of people being equally armed.
Likewise… the return to a class society would depend on the disarmament of society and the return to the medieval model of a Ruling Class and a Working class. Given enough time those Armed, will eventually Enslave those who are not armed.