Hello. One of the reasons for the Hi Power's continued popularity must be its very fine reliability. Having said that, I note that a somewhat FAQ concerns the Hi Power not ejecting the last fired case. Prior shots always extract and eject but that last round fires, the slide locks back and sure 'nuff, the empty case is lying atop the magazine.
I have a Hi Power in which this frequently occurs. It has not affected reliability at all but I can see how it could cause some concerns for those considering the pistol in a self-defense setting.
On all but the last shot, there is a cartridge in the magazine beneath the fired case being extracted as the gun fires. This keeps the hull from sliding downward on the breechface if the gun's extractor claw doesn't hold the case quite tightly enough to keep it from doing so. On marginal cases, the Hi Power might fail to eject the last hull with Brand X but never do it with Brand Y. The reason is slightly different rim thicknesses on the different makers' rounds.
The problem can usually be corrected by very lightly stoning the pad that bottoms against the slide in the groove in which the (external) extractor rides. Not much is necessary to eliminate the problem and this frequently takes care of it.
If the gun is failing to extract/eject on all shots, the problem is either a damaged extractor claw, a weak extractor spring, or both.