msta,
Think you will find that 00 buck does not nest (layers of three) in a 12 ga. hull with plastic wads that have the petals.
My experience,
I played with cutting the petals off AA wads - the red, white, and yellow - with varying results.
Cutting the petals off allow you to nest three layers of three 00 without bulging the hull.
Results were great for some of the shots and then you would get one that patterned off center.
Not sure why, but I was dissatisfied with the results, so I abandoned the effort and
switched to card and fiber wads as suggested in Hercules/Alliant loading guides.
The proper card and fiber wads - 12 gauge for plastic hulls - are available at most black Powder shops or on-line.
I also sleeved the buck with two wraps of grocery store store brown paper bag that helps to tighten the patterns of the buck.
It is cheaper than buying the mylar!
FWIW, Reloaded plastic hulls tend to deform or mushroom more quickly than factory loads when left compressed in a magazine tube.
I now reload my buck loads with brass hulls for this reason and the fact that the brass hulls are much easier (and less messy) to waterproof.
Nine 00 buck weigh around 1 1/8 oz.
Loads used Promo, Red Dot, and 700x for light loads 1150 fps., WSF for full power 1300 fps., but settled on Herco.
Herco was one of the old Hercules Powder originals (along with Bullseye) and the powder the company chose to give their name to for a reason.
It is a real performer in a shotgun as well as many high performance handgun loads.
JT
