Prior to the introduction of the Mk. II (1981) BHPs had what was called a "humped" feed ramp. The feed ramp change was to improve the feeding of JHP bullets.The Inglis barrel has a very "interesting" feed ramp. No ejection problems, using either barrel, and I am certainly not disappointed with that! The "brushed blue" finish on the external metal looks a lot like gray-green Parkerizing to me, but as that finish holds an oil film quite well, no criticism from me. The internal surfaces of the barrel are finished and polished beautifully (as is the Chinese Contract Inglis barrel I have).
From S. Camp...older Hi Powers, which have the old humped feed ramp. These definitely could have "indigestion" with other than FMJ round nose ammunition, not all but some. With the advent of the Mk II Hi Power in the 1980's, FN changed the feed ramp to a "straight" design and since that time, Hi Powers are reliable with about any JHP I've tried.
Shown are two 9mm Hi Power barrels from BarSto. The top has the humped barrel and closely resembles the FN factory bbl of humped design that was common in Hi Powers preceding the Mk II. The bottom barrel has had the hump removed and appears the same as the current straight ramp factory Hi Power barrels. If one is going to have a humped bbl's feed ramp made into a straight one, care must be taken to insure that most of the work is done at and below the hump. We do not want to remove any more steel than is necessary at the rear of the chamber. Improperly done, this can lead to insufficient case support, never a good thing.