If you get shot in a vital organ (heart, for example) its not really gonna matter is one round has 40 ft. lbs of pressure over another, or if it can go thru 14 inches of gelatin instead on 12. Bad Guy isnt likely to get up and say "Man Im glad that brand x ammo is 100 fps slower than brand y, I thought I was fixin' to get my birth certificate cancelled.." (Yes im cynical on the topic as well.) Find what feeds and cycles well, and stay with something you trust. My personal choice is Golden Sabres, just cause they were readily available and Ive never had a malfunction in my LCP. I just got a M&P 9c today, and its off to test their performance there too.