From the Hornady site
Simply insert a Hornady bushing into your RCBS® Rock Chucker or other reloading press using a 1-1/4-12 thread, and you’re ready to take advantage of Hornady’s Lock-N-Load technology. It’s the easiest way to get the most out of your competitive reloading press. The Lock-N-Load Conversion Kit includes three die bushings and one conversion bushing.
On the rockchucker there is a black threaded on inside and outside "nut" the 7/8X14 dies screw into. I believe if you remove that your Hornady adaptors will screw into the Rockchucker in its place. Then you can use the Loc-n-load bushings on your dies and keep the setup just like when switching around in a Hornady press. Catch is I bet the dies will need some adjusting when switching presses.