125 GR. NOS BT 2.060" IMR 4227 16.5 @1818- 17.7C @1965
IMR 4227 is the slowest powder Hodgdon's site lists, given that all powders are their own; AA1680 is even slower than that.
125 GR. NOS BT 2.060" AA1680 @ 18.2 grains is ~100% case capacity @ ~1900 fps but at only an ~80% burn rate:
http://www.quarterbore.net/forums/showthread.php?t=9319