Simple answer, no. Rhodesia was always less than 10% white. The reason Ian Smith and the white Rhodesians fought so hard against majority rule despite near universal international condemnation and trade embargoes was they knew that majority universal voting rights given to the black population would spell doom for the white citizens. As we all know, the black population in the U.S. is roughly 13% and expected to remain fairly constant. What isn't is the overall hispanic population.

Honestly if I had to make any predictions, in the coming years the U.S. will look increasingly like Brazil. A very racially diverse nation with high crime rates. There won't be any real black supremacy beyond symbolic gestures like more leading roles in medieval fantasy movies and more stupid made-up holidays, but I don't think the overall situation of african-americans will improve. Also as the hispanic population in the U.S. increases, black power will decrease because hispanics can't really be guilt tripped by the whole slavery and "evil white people" thing. Make of this analysis what you will.

To bring this back to weapons discussion, I would recommend anyone interested in Rhodesia to check out "A Handful of Hard Men". The shit the Rhodesian SAS pulled off is inspiring. I'm talking 200 men vs 10,000 and only taking 10 casualties as opposed to the ZANLA's 8000.