Two Piper is exactly correct.

Alliant does not list loads under 7,000 psi for just this reason.

My experience with Red Dot is that it's not worth a crap under 8,500 psi. Certainly the current production Red Dot can't be trusted under that. It's at it's best with a 1 1/8oz load, a name brand wad, and a goodly charge. Clean and complete burns then occur.

Promo works better in light loads, at least for me.

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