CASS, Singing Hills Ranch

Best for boom, smoke and flame. It burns a little more inconsistently, larger granules appear to be finishing further down the barrels

Are you using a single stage or progressive, or hand dipping powder and Shot. Nitro card over powder will, help your stack heights. https://www.ballisticproducts.com/Nitro-Cards/products/118/ Square loads work well, with BP (equal powder to shot) but then you need to adjust wad length for crimp. Hard to find a light shot cup with a large volume powder side.

Mine scorch and plenty of pickups available at the clubs from other trapshooters.

Cheerios inside the wad cup before you drop Shot can be your friend.

Your Windjammer wads aren't giving you enough room for powder. Using the shorter length wad you need a filler or increase amount of BP and Shot. The dynamics of BP don't allow "lite" loads. But even full loads don't have a hard recoil. That shorty red wad is what you want to use.

Based on your photos your wads are too short and too long. STSand gun club load the same. You will only get one safe BP reload out of your hulls. Might want to save the nice sts for smokeless. How are you measuring both powder and shot. We need to manipulate those to accommodate your wad length.

What hull are you using. What wads do you have on hand. We can start there. Picture shows 4.0 cc dipper BP (65 grains) Gun Club hull, Claybuster CB1138-12 12ga WAA12R wad and a little 0000 steel wool over the powder.