This discussion clarifies whether a sale from a registered person to an unregistered person is considered a Reverse Charge Mechanism (RCM) sale under GST. It's confirmed that this scenario does not fall under RCM. The registered seller is liable to charge GST on the sale, regardless of the buyer's registration status, and can claim Input Tax Credit (ITC).
As per Sec 9(4) of CGST Act, if a registered person purchases goods/services from an unregistered dealer (URD) then the registered taxpayer is liable to pay GST on reverse charge basis( only for certain goods/services & registered persons).
Oh sorry, I think you can claim ITC even if you make a sale to an unregistered dealer as you will be charging him GST on the sale no matter he is registered or not. this is not fall in Rcm