Orally, 10mg of oxycodone is considered equivalent to 15mg or morphine sulfate but everyone is different. Oxycodone isn't usually used medically by injection so a conversion is unavailable. 5mg morphine by injection is equal to about 15mg of oral morphine. 5mg morphine is probably about equal to 5mg oxycodone by injection.
So orally, oxy. is stronger!