Originally Posted by
megasupermagnum
Sure, many of us have done similar, although not quite to 1000 grains. You don't need any special case if you don't want it, even a regular old 2 3/4" plastic case fold crimped has enough room. I've been very curious about the Henry slug gun. If you don't mind, can you take a few measurements of the OD of the barrel in a few spots? Also, how much does it weigh if you have a scale?
You can use smokeless powder, but you have to know what you are doing. Blackpowder by comparison is about idiot proof. I couldn't even imagine how much black powder it would take to become dangerous, 200+ grains I'm sure, and I doubt you can fit that much in a normal shotgun shell.
The twist rate of that Henry is such that you should be able to stabilize those heavy slugs at a reasonably slow velocity. With a 1000 grain slug, I think 900 fps is a realistic number. A much easier path is to choose a slightly lighter slug, so that you can find shot data for them. In a 12 gauge, that is going to be up to about 875 grains at the top end, and even more data in the 656 to 766 grain range. If you search a member called Turbo, he used to mess with 1000 grain slugs, and he had data listed. I messed with a 950 grain slug once, but I think it's getting into the territory of too much of a good thing. I was even shooting them out of a 10 pound Ultra slug hunter, and I'd bet your Henry is lighter than that. Unless you get a gun 15, and ideally closer to 20 pounds, these really strong loads are pretty ridiculous.
If you go down to the special projects section of this forum, you will find a thread on someone shooting a "12 gauge from hell", essentially a 12 gauge full of rifle powder, yet running at reasonable pressures for a really strong gun, which I do NOT know if your Henry is up to. Anyway, you can find videos of him shooting super strong loads like 700+ grain slugs at 1600 fps up to I think he made it to 2200 fps or so in an Ultra slug hunter that he weighted to 14 pounds (don't quote me). The gist of it is, it makes a huge explosion on the targets, but the guys only ever shoot it ONCE. Numerous times I asked him to shoot a group with it, and after all this time he has refused. That should tell you.
About the most fun you can have is a .735" round ball. You don't need to measure your groove diameter for these, as long as your groove is somewhere in the ballpark of .725" to .735", which it will be, they shoot really well. Cast these of a strong alloy, and if you want extra hardness, water drop them. They weigh around 580 grains, and are an absolute animal with a hefty charge of Bluedot. I've not tried them in a shotgun shell with blackpowder, but the idea is the same. The only wads you need are an X12X gas seal, and a nitro cards. They shoot really well, better than most slugs I've tried. Penetration of these is on par with most solid 45-70 loads, but leave a gaping hole. The only deer I shot with them dropped on the spot with a nice big hole through the lungs.