KP1 locks it in place just as an Encore would.The KRB allows a bit of flex as the "block" is not really locked in position. The primer seating in a KRB is also probably not as fully engaged as it perhaps should be. There may be other, less obvious, issues regrading use of BH209 in a KRB. The "domed" Knight plug also seems to have issues with BH209.

The list of rifles the powder WILL function reliably in seems to be shrinking rather than growing. Lead conical shooters apparently need not apply.