I think it's laughable that the .38 Special (1899) is supposedly held back "because there's millions" of old .38 Special revolvers out there, while the 9mm Luger (1902) gets a pass with all the supposedly latest expanding bullet technology and +P and +P+ loadings, though there are also millions of old 9mm automatics out there, some of quite poor design strength and durability.

Nobody's concerned that any current 9mm Luger ammunition might be fired in any 9mm pistol design, materials, and degree of workmanship fielded in the last 121 years.

Why is that?