My guess being am older Sig like a P6, they were designed to use round nose fmj ammunition. I have a older P220 with the heal release and the feed ramp is significantly different from a newer P220. Thus hollow point rounds will indeed feed less reliably, but that's only a guess though.

The feed ramp on the left is from an early P220, with a heel magazine release, the feed ramp on the right is from a later produced P220. The ramp on the left has a much more pronounced curve at the base and the appears to be also a bit more concave in comparison to the other feed ramp. The newer feed ramp is square at the base and less concave leading me to conclude that the early feed ramp was definitely engineered for a RN FMJ round only. This is only based on my observation though, comparing the two feed ramps. I have never tried any Federal HST rounds on the left-hand feed ramp, although the newer feed ramp has not hiccupped once with hollow point reloads I ran through it recently.