I’ve read and heard a lot of good things about frangible 9mm & 5.56 for that matter. I haven’t tried any out but for self defense and close quarters it’s worth checking out.
The general thought is the bullet dumps the full energy load on contact and the bullet disintegrates into dust as a result. But that full engery transfer is what will stop some one in their tracks.
No. Same reasons as my post above, about Glaser Safety Slugs.
The performance of rifle vs pistol ammo, are wholly different.
Been following the research of Dr. Gary Roberts, on terminal performance of various manufacturer loads for rifle and pistol (he goes by, and is commonly referred to as DocGKR). His research has been used for Federal/DoD and Law Enforcement agency procurement contracts.
He's tested most of the available manufacturer loads for penetration and expansion in bare calibrated ballistics gelatin, fired through 4 layers of denim, and through auto glass/windshields.
As of now, the 3 top performing 9mm rounds are
Federal HST
Speer Gold Dot G2
Winchester Ranger-T (VERY difficult to obtain, without LE connections. Dealers are instructed NOT to sell to the public. Even many departments have switched over to HST or G2, due to supply issues procuring Ranger-T. I prefer RA9T over RA9B. Eagle Eye Guns for whatever reason, is one of the only places that will sell it to folks without LE/Mil credentials).
*** Honorable mention goes to Hornady Critical Defense and Critical Duty. Critical Defense has less penetration but better expansion in shorter barrels. C Duty is designed for better penetration, especially after going through intermediate barriers like auto glass.
As folks have pointed out, there is minimal benefit shown in testing, of the +p/+p+ varieties. As for bullet weights, either 124gr, or 147gr.
I prefer 147gr, but be aware that there are some guns/barrels that may encounter failures with some 147gr rounds. Common recommendation (besides firing a few hundred rounds of a particular load through the specific pistol, which realistically is always the best option), is to do a 'spin test'. If you can drop a live round in the chamber and manually spin/turn it, it should cycle fine. If it sticks, you might have issues.
Bone Frog Gun Club is one place I've purchased HST from (was going through some and saw the invoice for $360 flat for a case, back in 2018
). There are also some places offering LE Trade-in HST (Ammo that was purchased but never fired, and replaced after X years), at even lower prices.
There's actually a gen1 vs gen2 HST (not advertised). Only way to tell, as far as I'm aware), is inspecting a round. The gen2 HST bullet has longer skiving (supposedly to aid consistent expansion, but the original shorter skive bullets have still been one of the most consistent rounds in actual real world performance).