measurements
I took my budget Frankford Arsenal digital mic to the REAL's. Largest (front) driving band measures .512-.513" , occasionally I'd get one a thousandth or so larger. Moving rearward, the bands are smaller, but I did not record them. I mic'd factory 370 gr Maxiballs, they went .506 at the front band, consistently. I also mic'd the Buffalo bullets (385 gr) and they went .512" up front.
So I'd say the REAL's and the Buffalo's are the same diameter, and my conclusion is that the REAL's are not particularly over size, being so near the same dia as the Buffalo bullets. I will keep trying to get the REAL's to shoot, maybe an over powder wad, and vary powder charge and type....we'll see. And I'll keep cleaning, and a mallet handy.
It's no wonder the Maxiballs seat easier, at .006+" smaller. Oddly, they shoot better too.