Will there be any accuracy difference if I was to use the same load in remington brass that shoots good groups with winchester brass. Reason I am asking is my friend tried one of my loads and it did really good, but he wants to use remington brass instead.

Yes ! But have him try ,the change may be for the better.
Internal capasity ,brass hardness ,neck thickness ect all are factors .
I have even seen lot to lot changes . While usely not great , slight POI are common between differant lotts of brass.

Johnch

I have shot several loads in the old 30/06 with a mixture of once shot cases and found no differance in my groups. I was using a hunting load and figured that 1" groups would do and they did! I picked up 500 once shot cases of various brands out of the the range trash can free, and used all of them. I realize there is some differance in cases and some people prefer one over another, but unless you are looking for .250 groups most any kind will work. I will not buy communist made brass when I can pick up made in the USA! Those commie bastards have screwed this country enough and killed enough of my friends. I will never buy out of the nation to support those freedom killing, people enslaving bastards!