"Muh Fort Hood". Hassan was in the military with some firearms training, and was reported to have bought his gun with the intent to train with it, which he did, becoming proficient with it. He was capable and trained with his weapon. The soldiers he killed in many cases made easy targets of themselves by rushing him and closing the distance between themselves and him making his fatal shots up close and easy. Even with all this, 13 people killed and 30 wounded.
Seung-Hui Cho, nutbag extreme buys a Glock 9mm and a Walther 22. No military training, didn't personally train the way Hassan did with his firearm, was autistic whack job. His targets didn't run towards him to give him better shots, they ran away, hid, giving him poorer optimal shot opportunity. With his 22 and 9mm he killed 32 and wounded 17, a virtual complete flip of Hassan's performance, without the advantages.
Want to use a mass shooting as your evidence, I guess we can say safely that the 9mm Luger is vastly superior to the 5.7. Even in the hands of whack job autist with little preperation the 9mm was better than a serious man with better skills and shots with the 5.7.
Your own article states ELEVEN center mass shots and more than 2 chest shots. So you must be shilling or thrilling. Two non fatal head shots. Manning took two shots to the chest area, Hull shot twice in the back, Cooke shot in the head and abdomen 5 times, all which survived their wounds. We start taking in which area the "shoulder" covers, the survived chest shots, the survived head shots, no, its not the magic moon beam killer you and others make it out to be.
The police decided not to go with it because its a shitty performer. 5.56 is far more competent, especially in longer barrels, and not everyone needs or is best off with a super short carbine. Its not just cheaper, its better.
Keep on shillin, though.