Great info. Thanks everyone. I was under the impression that the SPRO swivels were stainless steel. I am guessing that the brass is the weak link in the barrel swivel. Looking at the following page, it says that the swivels are stainless. That being said, I do know of at least one that popped apart on a falconry bird. I use them, and do inspect the seam regularly. I toss them when there is enough play in the seam that they rock a little from side to side. Actually, I just use them for something else at that point.
http://www.cabelas.com/swivels-snaps...:referralID=NA