That is one of the reason I refered to when I responded to an earlier post yesterday about fire forming, Other than the cost of bullets when all you need is cream of wheat and a wad of paper to properly form a case, other posters have said the same thing. I have formed hundreds of cases over the years and have only used Red Dot shot gun powder.
One other thing I have always done was made sure was to elevate the gun first to keep the powder back against the powder.
When people ask about the noise, I used 30ft of 2in black pipe to shoot into after wrapping the last couple inches near the end of the barrel with a piece of cloth or foam to muffle the sound, works very good. Just my thoughts. Johnny G1