A Luger, even with the crude sights they have will out-shoot nearly any 9mm you can put your hands on, probably including some of the specific target models. Yeah, they are that good.
That's interesting. I'll bet the fixed barrel has a lot to do with that, well, and the extreme quality of workmanship if you can get one in good shape.
I've never owned a really high end 9, ain't in the HK income level.
Only ones I've owned are my Kel Tec P11 (a sub compact), a P95 Ruger, a P85 Ruger, and a couple of Chinese Tokarevs. The P85 and the P95 are typically nothing special, about 2.5" 25 yard groups off sand bags. That's good 'nuf I reckon, but nothing special. My little Kel Tec shoots to POA and puts 'em into 3.5" at that range which is pretty impressive if you consider the size of the little gun and the sight radius you're working with.
If I want 1" groups off the bags at 25 yards in an auto pistol, the only one I have that will shoot that well is a Ruger P90. That thing is awesome accurate and not really particular about what you're feeding it. It's my favorite of all my auto pistols, but it's in .45 ACP, which ain't a bad thing BTW.
The only other guns I have that shoot as well as that P90 are revolvers and a single shot pistol (scoped Contender, that's cheating). One reason I love revolvers for outdoor use is that sort of 4 MOA accuracy is the norm in affordable firearms and they can handle POWERFUL calibers, too. As you can see from this thread, a 9mm that shoots that well is going to cost you some scratch. To get some of 'em like 1911s to fire that well, you may have to sacrifice some reliability which is not a good trade off if you're thinking using it for defense.
For defensive purposes, though, to me, anything that'll put a magazine full into 4" off sandbags at 25 yards is probably more than accurate enough. That's my own personal standard. In reality, the ranges are going to be a lot closer. In the field, outdoors, you might have to shoot 50 yards, but in the concrete jungle 25 yards is a LONG ways and not really in the scenario. If you're that far away, chances are you can retreat.