Srhaggerty,
I have actually not used the 125 ULD RBBT. I have used the 130 gr Bonded Core FB bullet though and they seem to work very well in a 1-10 twist in most cases. I have seen a couple where accuracy was not up to par.
If your talking about the ULD RBBT I would say that I would probably recommend to say with the 125 unless the only difference is that Richard increased the weight of the core by removing air space in the HP. If this is the case, they should perform the same as the 125 gr ULD RBBT in my opinion.
Like I said, I have only shot the 130 BCFBHPs and with those I was in the 3450-3650 fps range so I can not say for sure how they would perform 500-700 fps slower in velocity.
Kirby Allen(50)