You all left out one difference, I know that the swabbing and the crud ring don't bother some people [the crud ring was a problem to me] and I know it will shoot reasonably accurate I used it for two years, and Sabot loader is right about the price it does change according to where you are around here they carry both in the local sporting good stores the 777 is around 27 and the BH is around 37 but I buy through a different system and get the BH cheaper than I can the 777 so circumstances change and vary for each of us but there is one point that a lot of people are missing.
With 777 yo can only burn about 120 gr effectively a bit of testing will show that with the same 120 grains that the pressure is around 15% lower and because it is progressive burning you can burn more and that after 110gr the difference in velocity will change as the BH keeps right on gaining. Just what I think from my own experience and testing. Lee