It's not that low pressure loads are inherently dangerous, but that reduced charges of slow burning powders are best avoided in ALL applications.

Jim Legg who did quite a bit of target shooting with 'reduced' loads recommended the old Nitro 100 when it was still available and had published loads in the 5-6K PSI range.

The idea is a moderate peak pressure spike and a pressure curve that rapidly falls off when the load clears the chamber. The chamber being the strongest part of the barrel of course.

"The price of good shotgunnery is constant practice" - Fred Kimble