The FPB like BH209 is designed for the best guns and the best shooters and seems to consistently work best for most people who are willing to put out the effort to use them right. The loads they work well with seem to be 90 up to 110 gr which are good loads for a conical of 350gr they have worked well in most TC guns the QLA makes loading relatively easy and a lot of the TC guns including 3 of mine will group in or near a minute of angle.
I have used the for boar hunting with excellent results usually getting passthroughs with excellent penetration and so far my experience indicates that they tend to be much flatter shooting than other conicals. They are not a cure all as there are much flatter shooting sabot bullets but with in 150 yds they do quite well. Lee