Starting to mold slugs. The mold is a Lee 1 ounce drive key. It is a cross between a foster and a sabot and is referred to as a wad slug. It can work in a rifled or smooth bore. The key in the base is supposed to engage rifling. People have good results through smooth bore because it is a foster as well, nose heavy hollow expandable base. I need to get out and shoot them but here is the start. I will be putting these in AA hulls at 1580 fps and in Remington Gun Club/STS/Nitro hulls at 1450 fps.
Here is how the Lee slug engages the wad. The idea is the wad catches rifling and the key of the slug digs into the wad there for imparting spin on the entire payload like a sabot. The slug and wad separate and the slug flies off spinning.
Here is a recovered wad showing how the bottom of the slug engages the wad.
The Lee slug is more interesting than you would think at first glance. You can see how one could think it is a sabotage, but it is not. It is a nose heavy foster slug. Why? This is the genius of the design.You can get good results using it in a rifled or a smooth bore. It is called a wad slug.
One of the tricks to accuracy out of a smooth bore is a clean separation of the slug from the wad to enter the nitro card. The card is very hard and will not dig into the slug or the wad. So you are just using the wad to transport the slug through the bore and take up room as the slug is only .69 cal.
Smooth bore set up
The trick to adding the card is that you have to make room in the hull by either a shorter wad or less powder. I have been playing with this and had good results doing both. This plays with pressures but ultimately cutting down on charge is safe and shorter wads are working for me as they weigh less than the wad called for in the recipe. One could nitpick this to death though.
One of the advantages I am finding is no leading of my barrel like I had using full bore size foster slugs
Went out with 8 different loads to try. I found the lowest grain of Herco and the highest grain of Accurate #5 to be the best grouping. I shot 5 of each totaling 40 rounds theses were the best groups. Just went 25 yards for the testing.
5 shot groups
Shot from a Mossberg 500 with a Vang Comp barrel 20" smoothbore
30 grains Herco, WAA12R 1/4" card 1 oz lee slug, AA hull
38.5 grains Accurate #5, WAA12SL no card 1 oz slug, Rem. Premier hull
They all shot well and I had 32, 34, 36, gr Herco with different card thicknesses. Accurate #5 in 36, 34 and 32 gr. The 38.5 gr Accurate #5 loads felt about like a 300 win mag in recoil bear loads. The 30 gr Herco loads were stout but felt mild compared to the rest. After I shot the groups at 25 yards I started going for the 100 yard gong and was hitting more time than not so I am thrilled.