On a scale of 1-10 with 1 being no resistance at all like a ball bearing to 10 being rock solid unmovable, How tight are the shackles at the end of your swing arms as show in the photos below?
Also how many threads back is the end of the bolt? Or does yours protrude out of the face of the shackle?
Mine were 10 unmovable and I loosened them with pliers but now see the threads are not fully engaged and concerned about that. If I tighten it slightly more it becomes almost unmovable.
Also see video in this OneDrive link of how I have it now, one is much looser than the other but they’re both not fully free swinging.
On my X4 the bolt threads protrude through the hole a bit. I’d definitely ensure the threads are at least fully engaged.
Also, the other end of the bolt should have a hole in it. Run a steel wire or split ring through that hole and around the u-bolt or arm so that the bolt can NOT back out. If using a wire be sure you can’t catch your forearm, or a riser, on the cut ends. Check the wire in your preflight.
In Nuclear power, we can’t use shackles for lifting if it doesn’t have full thread engagement to edge of shackle. Personally, I wouldn’t use those myself to fly
The swing arm shackles hold the seat up. If one should let go you slide out on one side and hang on the leg strap. Not fun and probably a cause to land asap. Not life threatening. The carabiners are … more critical.
