Allan, what COL did you seat the 275s to and what kind of crimp did you employ and to what degree. IE Taper crimp to .476
QuickLoad, which can be hit or miss with this caliber says Enforcer is awfully fast for that bullet weight. More appropriate to the light stuff others have mentioned. QL says your bullets were running around 2100 fps. Again, it is more often wrong than right with the 450b outside the factory load components. That is, until you calibrate to your first results. Then it tracks very well for predicting what to expect when you vary those components. Aside from Lil Gun and the 250 FTX, the only other powder I've gotten uncalibrated predictions that were right, was with Vihtavuori N110. Some other combinations are close without requiring too much fiddling, but rarely right,so you may have gotten a different velocity than predicted for what that's worth.
From my experience with the 275s, they are incredibly forgiving with different loads, most producing excellent groups. Both the 200s and the 275 XPBs shoot very well, but for what they cost, they ought to.
Hoot
EDIT: My favorite Barnes XPB Porn: