...without special work being done.
This statement was sometimes true enough with the classic style Hi Powers predating the Mk II, which debuted in 1982. At that time, FN "throated" the old "humped" feed ramp. This change took the Hi Power pistol from being potentially "picky" about which JHP's it would feed to one that has proven not to be particular at all. In other words, Hi Powers in the Mk II or current Mk III designs are very reliable with expanding ammunition having blunt bullet shapes.
Can there be the individual Hi Power that fails to feed? Probaby so; individual specimens that are not up to snuff occassionally seem to slip past the QC personnel of more than one manufacturer. I have shot more than a few Hi Powers over the past 4 decades. From my very first Mk II to my current Mk III's, I have yet to see a single one that wouldn't feed FMJ or JHP's in bullet weights of about 90 grains to 158 grains (heavy Israeli subsonic loads).
Current 9mm Hi Powers feed reliably and the old saying that they are "jamamatics" with other than FMJ ammunition just is no longer true...and and hasn't been for 28 years!
The Hi Power may or may not be a 9mm pistol that curries your favor, but if weighing factors in making that decision, don't buy into to the outdated "facts" that Hi Powers won't feed other than ball rounds. 9mm Hi Powers made from '82 onward will...and those made before 1982 can be made to without much difficulty! (Having said that, I fully understand that some shooters will simply prefer other designs to the Hi Power; there are many quality 9mm autoloaders to choose from; go with what works for you in my view.)