Another vote for Federal HST 9mm +P. The +P isn't anything excessive, adds 50fps to the projectile for almost nothing in terms of cost. I prefer the lighter 124 grain projectile. I understand they make a 147 grain version, standard pressure and +P. I'm sure most of you have seen the LuckyGnner Lab testing? If not here is the link to what is arguably one of the most comprehensive analysis of gel block ammo testing. They utilize the standard FBI protocols, including the 4 layers of denim. I looked for the bullet that came together at the intersection of expansion, adequate penetration, and velocity. The clear winner, IMO, was the 124 grain HST +P. I favor a projectile that nears the upper-end of the FBI penetration threshold of 18 inches.
Here is the link to the site and the test.
http://www.luckygunner.com/labs/self-defense-ammo-ballistic-tests/
Here is link to the 9mm HST specifically
http://www.luckygunner.com/9mm-p-124-grain-hst-hp-federal-premium-law-enforcement-50-rounds#geltest
A close second seems to be the Remington 124 grain 9mm +P Golden Saber. It's almost identical in how it performs compared to the HST 9mm +P.
http://www.luckygunner.com/9-mm-p-124-grain-jhp-remington-golden-saber-25-rounds#geltest. The HST obtained a greater penetration average verus the GS 124G +P due to having 2 test rounds exceed the 18" mark, while the GS only had one.
These results are so detailed its' incredible. Some rounds have better expansion but poor penetration, such as the Barnes 155 grain TAC-XPD 9mm +P.
The heaviest projectile that achieved the greatest penetration and expansion was the Federal 150g Micro HST 9mm. It achieved an incredible .71 inch average expansion, penetrating to an average of 17.3 inches while only moving 888 FPS. That is incredible. I've always favored faster moving, lighter projectiles. Think the old Corbon 115 grain +P. I've used tons of that. But there is evidence that has shown these short-barred firearms can deliver better terminal ballistics with slower and heavier ammo. Federal specifically produced this "Micro" line of ammo using this premise. I think I might give some a try. It's god-awful expensive though.
http://www.luckygunner.com/9mm-150-grain-hst-jhp-federal-premium-20-rounds#reviews. Can anyone with more experience with this ammo explain how a heavier, slower projectile performs better from a shorter barrel?
My practice round is CCI Blazer brass-cased.