What is the internal diameter of a barrel rifle? Is there a formula to calculate it based on caliber? Or does the diameter exactly match that of the bullet? For example, my
![Bought a rifling button in 5.6mm to make .22 barrels but i thought the 5.6mm were going to be the cutting flutes but it is the size of the pilot guide and Bought a rifling button in 5.6mm to make .22 barrels but i thought the 5.6mm were going to be the cutting flutes but it is the size of the pilot guide and](https://i.redd.it/20qr7py6a0r91.jpg)
Bought a rifling button in 5.6mm to make .22 barrels but i thought the 5.6mm were going to be the cutting flutes but it is the size of the pilot guide and
![hammerbutton Chamber Reamer+Combo Rifling buttons (Chamber Reamer+Combo Rifling button 45ACP), Silver - - Amazon.com hammerbutton Chamber Reamer+Combo Rifling buttons (Chamber Reamer+Combo Rifling button 45ACP), Silver - - Amazon.com](https://m.media-amazon.com/images/I/71j8CeJBFxL.jpg)