
Bet you it wasnt cast, but wire formed... it worried me when thats happened to me, and i found that the ring had opened up as it was unwelded - hence i only use cast brass unless someone specifically asks me and then i use welded stainless steel.
Worrying though, ive had welded steel rings STRETCH over time! possibly wasnt stainless though.. not sure (was a dog lead i bought off the market, so not one of my own).
A lot, in fact the majority of leather collars and leads on sale here are made using very low quality leather (especially if its coloured where the colour appears like paint on the surface), or offcuts from the upholstery or handbag trade - its NOT strong enough for the job, but it is so cheap, a collar you might pay a tenner for has cost around £1 to make, as it only takes minutes to machine sew on a lining and rivet it all to a buckle.
Does make me want to cry sometimes especially when i see leather goods advertised as quality english leather, hand made, when i know but most people cannot, that its reject standard leather, machine sewn and mass produced. Mostly

as thats my competition but also as a lot of the items are just NOT safe.