This was an interesting project I had been thinking about because one of my nephews wanted Snake Shot for his 40S&W, well CCI dropped production a while back.
Here is what I did to make these, first I started with an old split 10mm casing properly sized and chamfered the inside and outside of the case mouth. This was used to cut wads from old primer tray covers, 2 for each round.
Then got several 10mm casings properly sized & primed with a CCI 350 Large Pistol Primers.
Next was hand weighed 3.5 grains of Alliant Red Dot powder and placed in the prepared cases, inserted one of the cards as a powder cover and then the second on top of the first keeping them squarely seated on top the powder.
Next I ran the cases into the 9x25 Dillon forming die, this puts a 9mm neck on the 10mm casing where the shoulder is set back to allow the casing to fit a 40S&W chamber. Then I ran these into the RCBS 9mm expander as set to slightly flair the now formed 9x25Dillon casing.
Then I filled the casing with shot (I only had #6 mixed with #7 1/2) however #9 or #12 would be better to use for this project. Leaving a little room, I pressed a .35 Cal Gas Check (cup up) on top to hold the shot in place. Once it was pressed down even to the case mouth, I taper crimped inward to finish.
Managed to test fire the round from my G-29 with the LWD 40S&W conversion barrel and the results were great even though the shot sizes were larger than desired.
(https://s20.postimg.cc/mevushegd/IMG_0006_zpsxq49t5ib.jpg)
(https://s20.postimg.cc/3mjzowprx/IMG_0005_zpsyuyesg7w.jpg)
Shadow snake ammo inc.
I'll by a box.
I wanted to mention they do not cycle the slide...and feeding from the magazine can be problematic, as they can hang up feed ramp as tested with the G-29. I will need to see how they do from an actual 40S&W firearm.
I will also investigate another method of topping them off that my add to better feeding.
How about the same way as mention,powder,cardboard cover,shot,then wax?
Wax in thin sheets would contain all, pressed on top....a heavy taper would assist in the feed...sort of like wad cutters...prob still have to manually feed tho.
That's awesome, now you just need to top that load of shot with a wadcutter.... just kidding, but that is awesome.
The gas check is taper crimped in place, I'm trying to find a few 10mm Magnum cases or 6.8 cases to see how they would work for 10mm use.
I have even thought about using plastic 2 liter or other plastics and heating them to mold some sort of shot cup... ::)