Can anyone point me to an article or information on the advantages and disadvantages of a rifle barrel cut with a variable twist, slow to faster. I can see a possible disadvantage at least in the manufacturing phase, but I'm not sure of any advantages. How much of barrel twist is required for proper bullet stabilization? In other words, if I have a 30-inch .30 cal. barrel, and the first 20-inches were smooth bore and the last 10-inches were1/10 twist could I impart enough spin to the bullet to stabilize it. If I have shown my ignorance of the law of physics in anyway, I apologize before hand. Thanks.