Dillinger is correct. If you would like to look into it further. Go to the above Search Box and type in Barrel Twist and hit GO.
Then scan down the topics and you will see a section titled "Understanding Barrel Twists" Maybe that will also help.
The Constitution is not an instrument for the Government to restrain the people. It is an instrument for the people to restrain the Government!
“Americans have the right and advantage of being armed. Unlike the people of other countries, whose leaders are afraid to trust them with arms.”
James Madison. Author of the 2nd Amendment