Hornady XTP bullets are very good for an older design, but newer ammo is often even better performing and better priced.
From Hornady 2011 TAP report
-----------------------------Bare Gelatin Performance Test-----------------------
Ammunition: 9mm 124 XTP 9mm 147 XTP
Weapon: Glock 19 Glock 19
Velocity: 1028 996
Total Penetration: 13" 15.25"
Max. bullet expansion (in): .610" .520"
Retained weight (grains): 123.8 138.5
-------------------------Heavy Clothing Gelatin Performance Test-----------------
Ammunition: 9mm 124 XTP 9mm 147 XTP
Velocity: 1057 1005
Total Penetration: 18.75" 17.5"
Max. bullet expansion (in): .490" .530"
Retained weight (grains): 123.6 146.9
--------------------------Sheet Metal Gelatin Performance Test-------------------
Ammunition: 9mm 124 XTP 9mm 147 XTP
Velocity: 1029 1009
Total Penetration: 18.25" 16.25"
Max. bullet expansion (in): .440" .510"
Retained weight (grains): 123.1 114.9
Notes: Jacket
separation
---------------------------Sheet Rock Gelatin Performance Test------------------
Ammunition: 9mm 124 XTP 9mm 147 XTP
Velocity: 1051 992
Total Penetration: 14.75" 18.00"
Max. bullet expansion (in): .510" .460"
Retained weight (grains): 123.6 146.6
---------------------------Auto Glass Gelatin Performance Test -------------------
Ammunition: 9mm 124 XTP 9mm 147 XTP
Velocity: 1034 985
Total Penetration: 10.50" 12"
Max. bullet expansion (in): .595" .570"
Retained weight (grains): 86.1(1) 98.8(1)
Notes: (1) Jacket separated from the lead core