Mission Reward Farming

I was wondering how you go about farming mission rewards (such as the sandhawk) on the next-gen versions. On 360 you could just duplicate your saves and use the secret stash but this method was eliminated on the Xbox One

The way to do it is dashboard until you get the item you want. Dashboarding stops the game from saving so you can complete the mission as many times as desired.

i mean more like if you wanted multiple variants of a single mission item. Such as farming for a corrosive and shock sand hawk