5.7 vs 9mm: Complete Handgun Caliber Comparison by Ammo.com

The FN5.7 is basically a shortened 5.56. The ballistics are relatively impressive compared to a 9mm. I'm going to wait until I see if other ammo manufacturers are going to produce the round, it's scarce and expensive around here.

Brother Rick, in my opinion, any caliber works, if it makes a hole in the body, it works. I've seen twice, a 22cal. put the person in the ground, even a speargun once.
But you kind of hit it on the button, if you only like shooting at a far range, and if your caliber is right for you, than, by all means, stay with it.
Myself, I like up close, maybe it's because, of my working as a COP for years, and always having to stand face to face with any threat.
I do shoot alot at 30 feet away, at a 8 inch target, if you can do that, than anything less than 30 feet is easy. Why 8 inches, well the norm size of a head is 8 inches, and or, the center of body mass.
I also shoot at 100 feet away, with my hands guns, just to give confidence to the other younger shooters, that happen to be shooting with me.
There is alot of talk of caliber, gun platform and etc., and it's all fine for them, but in my opinion, honestly, "Round Placement is King".
While in the Army infantry, I'd rather have a 105 round used, than my 5.56 out of my M-16, at the enemy.
Think about it, the Airforce takes a 1000lb bomb, and uses it, to kill one guy, Hey it works.

When the mental becomes physical, let us know what you think then