I pulled on a version of this shackle but this time I pulled on the loop without using a ring hitch. This would stress the spliced area fully as there is no additional force holding it together as there is when it is in the ring hitch. This bury was 23 diameters and was made of 7/64 Amsteel so that I would break it with my winch. It broke at near the maximum force I could put on the winch handle with the 35 power winch. That would be close to line strength plus or minus. What broke was the stopper loop (top of first picture below) that the shackle was attached to.
My next test was to use the ring hitch to attach the shackle to the 7/16 XLS that went to the winch. The eye of the shackle was attached to a 3/16 stopper loop to remove that as the failure. The shackle broke at the eye. The 7/26 XLS was stretched 17% when the shackle failed. My estimate is between 2000 and 3000 pounds, more than the line strength. The loop with the 23 diameter bury did not fail.
