I use only Hornady or Forster lock rings. Makes loosening to adjust dies much easier.
If you use the RCBS lockout die, make sure it stops the press with either an empty case or a double charge. I was loading light .38 Special loads (3.5 grains of Win 231) and discovered by accident that it did NOT lockup the press on an empty case. I double checked the adjustment and it was by the book. Don't trust it now and am happy I was double checking every case by Mark I eyeball.