I just posted this on another forum that has a thread on Federal 147gr. +P+:

Update, FYI: After doing a long-overdue trigger job on my 4" 10-8, I decided to run a few rounds of this ammo over the chrono Saturday.
Temp: Approx. 70 deg. F
RH: Approx. 90%
For three rounds: Mean vel.: 1063.9 fps.
H: 1090.7
L: 1035.7
ES: 55.0
KE: 370 ft.lbs.

This particular gun has a tight barrel/cylinder gap, and runs fast. It got an average of 943 fps. with FBI loads from the same box that got 771 from the Magnum Carry.