I read this while back.
9mm 115gr 1250fps 399 ft lbs
5.7mm 31gr 2346fps 379 ft lbs
.22 mag 33gr 2000fps 293 ft lbs
Our recent tests also show that mass is more important than energy calculated in this manner. Considering this, a 31gr projectile is an abysmal performer. Tests show it does no better than the slightly slower .22 mag in killing even small game.