I've read and seen tests done with the blind bolt. With a partial ball in the chamber, the blind bolt hits it and bounces off with no damage to the pb. I have a 2 minute vid of it. The blind bolt is a delrin bolt( I wish Nylatron) with a rubber tip on it that makes it bounce off of partially entered balls.
Other bolts are Delrin/Nylatron fully, no real soft part on them, so they just hit the partially in-chamber ball and chop it in half, damn chops.