Has anyone ever tried cables made with OCC (Ohno Continuous Cast) Copper?

Nothing new here ... OCC copper cables have been around now for a long time and there are many cable manufacturers offering them.
As far, in general,  OCC cables “sounding better”, there is no silver bullet upgrade and improvements solution here because,

(1) OCC brand1 can (and frequently will... ) sound “different” ( = not necessarily “better”....) than OCC brand2, and/or compared to silver cables and/or hybrid options.

(2)audio improvements ( ... or not ) are entirely listening room and system dependent .

(3) there are many other cable material options that work well or better (depending on the bespoke system in question) including, inter alia, silver and hybrid copper / silver offerings.

(4) Conversely, all the upgraded cables in the world may not invoke audio improvements in certain systems ... full stop.

Until you actually roll up your sleeves and hands-on experiment yourself in your bespoke listening arena and on your system, you wont know .

like akg_ca said, OCC is an indicator, but not the ultimate deciding factor on how well a cable sounds.  There are other considerations, such as type of metal (copper/silver), strand size and bundling versus solid core, geometry, shielding, terminations, etc.

That being said, OCC copper and ultra-high purity copper are generally much better sounding than normal manufactured copper, which can be OFC (or oxygen free copper).  The smoothing of wire metal surface also plays a factor in signal clarity.

I changed all my cables to OCC ones. Less gritty, smoother and more depth. But it always depends on the implementation and geometry. I use the Ramm cable with air dielectric for power. Very happy with the result. Neotech power cords are also very good. (more slam/less open). I also changed all my connectors to pure copper/tellurium ones. Bigger bottom end, blacker background, enhanced s/n ratio.