Some more info-- the 12ga Helix cushion driver 18 wad is what
I mentioned and it is over 1/8 inch shorter than the 12ga trap commander
and alot more shorter than other majority of other wads
so more powder room. I mis-spoke the 525gr above was a lyman slug and I've
also used Lee Key 1 oz slug. Along with 3 inch case we have the room,
for 90gr 4759....
The reason I mention a minimum of 70gr in 12ga is so that we don't
have delayed ignition. And you can't get enough powder in with
slugs 600 gr and under to hurt any modern medium weight
barrel gun or action.
The 4759 powder gets to peak pressure so much slower and easier
than regular shotgun powders, that it is much easier on cases and wads,
so much so, you don't need cards under the slugs that take up space.
On most loads with Helix cushion driver 18, I use one BPGS seal with it,
they fit together perfect.Ed.