Semi auto barrel length includes the ramp and chamber so a 4 inch 9mm has about 3” of twist, same as a 3 inch revolver. (But I have no idea what Minguez is trying to say.)
All subsonic handgun rounds work by causing blood loss. Supersonic rifle rounds work differently. Extra velocity shoots flatter long range. Any caliber and any barrel length works if you hit the brain stem or open a major artery and cause the lifeblood to flow out.
Isn’t he is comparing 9mm+p with 38 special?
Right, any way you slice it doesn’t make sense. I assumed he was referring to .357 Sig, since that’s what is being replaced at the Secret Service (but then why mention .38?), and barrel length is measured the same. Maybe he means a revolver with a 4” barrel is much longer than a Glock with a 4” barrel? But why is that relevant here?
The P229 carried by the Secret Service actually has barrel that is a tenth of an inch shorter than the Glock 19, 19X, or 45. I assume the new Secret Service Gloc is one of those and not the even longer-barrelled 17 or 34, though I think either would be a better idea than the 19 for what they need.
Most 9mm duty loads and pretty much all .357 Sig loads are supersonic. Maybe not fast enough to cause serious hydrostatic shock, if that’s a thing, but these aren’t subsonic rounds.
A Cor Bon 9mm 125gr +P makes 1226 fps out of a 4” barrel. A Cor Bon .357 Sig 125gr makes 1496 fps out of a 4” barrel. The .357 Sig is just far more powerful than the 9mm out of any barrel length—it was intended to give you something analogous to .357 Magnum ballistics out of an autoloader with 9mm/.40S&W sized magazines.
Now, does that power actually translate into more effectiveness against a live target, and enough to offset the increased recoil, wear on guns, and ammo costs? That’s controversial, of course. But that’s not what this guy was saying—he was actually saying the 9mm gets better velocity out of a shorter barrel, which is ludicrous.