prisoners brings, and occasionally win, lawsuits for the violation of their civil rights, so there is no bright line that prisoners give up their constitutional rights. However, it is understood that restrictions on certain of their constitutional rights are appropriate given their situation. Prisoners didn't have the right to guns in prison when the 2d Amendment was proposed, debated or ratified and no one at the time believed that "the right to keep and bear arms" encompassed a right to have them in prison. The "right to keep and bear arms" is the right as it was known when it it was added to the Constitution.