Paul broke a prussic cord attached to a ring, just like the one you have there ,for me awhile back and it broke around 8,000 lbs. If I remember correctly, it broke at the taper of the stitched brummel. I had a locked brummel on one side and a stitced on the other. The stitched brummel wasn't even lock stitched. He made a video of the break test and posted it on the old site. The thread was called Break Stuff.