I have done extensive ballistic gel testing with 9mm Shield and Glock 43.
The Federal HST 124 gr standard pressure has been stellar. 18" penetration with average of .622 expansion (or close to that number) I have tested over 25 rounds of HST 124
The other great round is the Corbon DPX 115+P...Penetrates to 16" with .685" expansion
No other rounds were as consistent as these two in regards to expansion and penetration. 4 Tests were done consisting of bare gel, 4 layers of denim, one layer of 5.3oz cotton and winter wear of nylon outer shell and medium weight insulation, 200gr polartec fleece and one 5.3oz cotton tshirt
I carry Federal HST 124 standard pressure. It performed well in every barrel length...G43, G19 and Glock 17