Hello,
Accuracy in 30 cal has given me 1 1/2 in groups @ 50 yds from a 1900AE & old Western ammo. I did similar groups ( just a tad wider ) with a 1920 3 7/8 in bbl & WW Super X ball ammo.
9mm: Best was around 1 1/2 in group @ 25 yds from various P-08's with factory & reloaded ammo. P-38's : well! it's not even worth mention as they are poor shooters, accuracy wise....
Best accuracy I ever had with a factory pistol in 9mm was 7/8 in @ 25 yds from a H&K P7M8...
So for me the 30 Luger is more accurate than a 9 mil...and I just built myself a nice 5 inch 30 cal Luger shooter for this season....
kidvett