Air held below centerline for gyroscopic backspin
Quarter turn radius for smooth airflow
Oval opening for wider unrestricted airflow
SofTouch Blot insert with raised lip
Alien's use of a two-piece bolt for below centerline airflow allows for pleanty of room to lock the SofTouch bolt pad in place. The blowout, common with others, does not happen with an Alien
Barrel breaks are not usually caused in the barrel. It is transitioning the ball from the feedneck into the chamber and the bolt pushing the ball into the barrel. The term loading fracture is used to describe these breaks.
The large front of the SofTouch pad with it's raised lip contacts the balls before they can drop into the chamber. Loading fractures are greatly reduced by having both the chamber ball and the ball in the feedneck contacted by the SofTouch Bolt Tip.