Sampo vs Barrel Swivel
While working on a book I investigated the internal nature of both the Sampo and Barrel swivel. It is easy to draw some conclusions after seeing how these swivels are made.
Also, a friend from Montana was placing what could be called "Grouse Deflectors" on fences in areas where Sage and Sharp-tail Grouse commonly fly over barb-wire fences placed on high areas in a local flyway. The number of dead grouse convinced him that some sort of spinning deflector was needed to condition the grouse to choose a different course thereby saving their lives. Just by chance he happened to use both Sampo and Barrel swivels on the small spinning deflectors.
What he found was very interesting. The swivels spun around powered by the wind at a good speed and were very effective in turning the grouse from that pathway. However, the barrel swivels came apart in short order. The swivels were put under extraordinary load and use. The Sampo held up to the abuse but the brass rivet in the internal portion of the barrel swivel actually reformed (or deformed) during use resulting in swivel failure. The Barrel swivel was a 570# model and the Sampo swivel was a 300# model.
Although this is extraordinary use and the hawk on the lawn will only place an equal wear over an extremely very long time, it is nonetheless worth mentioning.
I have placed a small * on the images in the spot that will first show wear in a swivel. If that area becomes loose and a small gap appears then the swivel may needs replacing.
I don't normally make postings on the Forum but I thought this was very interesting. My time in responding will be limited but I would like to read the discussion as the Barrel Swivel has made a place for itself since the advent and common use of the braided tethering system.