This is an anti rollback mod, but the difference between this and other one is that it stops the balls from actually rolling into the bolt face
#1 Get a sharpie and mark 2 points on the very tip of the bolt on opisite sides.
#2 Get 1/16 drill bit, and drill through the dots that you made.
#3 Get an oring with a thickness of 1.16 and cut it in half and stick through the holes.
#4 Cut off exess of the oring, and glue with super glue in place.
And it should end up looking like this.