@NitroFury
Sure! It’s only practical with low-pressure cartridges that generate a relatively low volume of propellant gasses, but sure. Look at all the .22 rimfires and pistol-caliber semiauto carbines.
There are engineering textbooks that touch on this topic. If you want a straight-blowback semiauto rifle in .30/06, the bolt has to weigh a minimum of seventeen and a half pounds.