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jordanka16

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Been posting about this on cast boolits because it's kind of a specialty forum, but I figured I would post it here too.

I'm going to start loading bore diameter 12 GA slugs for a rifled bore slug gun. Many others have done this before me but not recently from what I can see. The general idea is to use slower powders than a shotgun would normally use, to slowly push much heavier slugs than is normally able. I'm going to try out up to 800 grains including some roundballs, but I also intend to try out 1000+ grain slugs. I found a design from years ago and made a drawing from the photo of the mold and also added some tweaks.

Anyone here play around with this stuff? It's pretty much just for fun, since there is no dangerous game here in Oregon, maybe you could use it against a bear but a 1050 grain slug going 1100 fps is a little much for a black bear, lol.

Screenshot (5).jpg
 

jordanka16

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What type of pressures you getting running slower powders and heavy loads out of the pipegun?
Same peak pressure as a standard shotgun load, max 11,500 psi. The difference is that the pressure is maintained all through the barrel, rather than just at the breach. So you don't want to attempt this in a normal shotgun tube, as they are too thin forward of the breach to take this repeatedly.

The Henry single shot I have could almost certainly take the 14,500 psi of a 3.5" shell, but assuming I can add some weight to the gun the free recoil of a max load will already be more than a 50 BMG, so probably not necessary, lol.


You can go back and read, there were a few guys years ago who started this and sent a lot of shells off for pressure testing to ensure they are safe, I have been talking to one of them and getting some updated data, the other guy I can't seem to get ahold of.
 
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Same peak pressure as a standard shotgun load, max 11,500 psi. The difference is that the pressure is maintained all through the barrel, rather than just at the breach. So you don't want to attempt this in a normal shotgun tube, as they are too thin forward of the breach to take this repeatedly.

The Henry single shot I have could almost certainly take the 14,500 psi of a 3.5" shell, but assuming I can add some weight to the gun the free recoil of a max load will already be more than a 50 BMG, so probably not necessary, lol.


You can go back and read, there were a few guys years ago who started this and sent a lot of shells off for pressure testing to ensure they are safe, I have been talking to one of them and getting some updated data, the other guy I can't seem to get ahold of.
Ya, I was thinking the curve would be way different. Getting closer to pipebomb than pipegun! I commend the project and look forward to hearing more!
 

jordanka16

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Ya, I was thinking the curve would be way different. Getting closer to pipebomb than pipegun! I commend the project and look forward to hearing more!
It's pretty amazing what kind of performance you can get with the slower powders at such low pressure. The problem is finding suitable powders, as most rifle powders don't light that well in big shotgun shells, and then a lot don't burn well or they burn erratically at low pressure.

For the most possible performance he recommended 1100+ grain slugs and a starting load of 120 grains of RE26, but I don't think I have the balls for that.
 

jordanka16

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Black powder? Black powder substitute?
That would certainly work, easy too. Fill case with powder, place slug on top, pull trigger.

That was my original plan actually, like an old british double rifle. But then I discovered the work people did proving smokeless was safe and could develop incredible energies, so I'm going for that now.
 

jordanka16

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How do you measure the pressure?
I personally don't, I'm using loads others developed. They sent their shells to a lab and had them pressure tested.

As a side note, you could actually do that yourself to your own loads if you wanted, from what I read it costs about $20-$25 to have a string of 5 shots tested.
 

TTSX

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It's pretty amazing what kind of performance you can get with the slower powders at such low pressure. The problem is finding suitable powders, as most rifle powders don't light that well in big shotgun shells, and then a lot don't burn well or they burn erratically at low pressure.

For the most possible performance he recommended 1100+ grain slugs and a starting load of 120 grains of RE26, but I don't think I have the balls for that.
Would that fit? Most .50 BMG loads I see have around 250 grains of very slow powder pushing a 660 grain bullet. Doubling the bullet and halving the powder would still take considerable volume, especially since not much of the slug sticks out....
 

jordanka16

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Would that fit? Most .50 BMG loads I see have around 250 grains of very slow powder pushing a 660 grain bullet. Doubling the bullet and halving the powder would still take considerable volume, especially since not much of the slug sticks out....
It does, possibly just in a 3.5" shell, but I think it does as well in a 3" shell.

That 660 grain bmg bullet is both copper and lead, and designed to be streamlined, the shotgun slug is all lead and very squat, taking up less space.

The inside diameter of a 50 bmg case is actually almost exactly the same diameter of a 12 gauge shell as well.
 

TTSX

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It does, possibly just in a 3.5" shell, but I think it does as well in a 3" shell.

That 660 grain bmg bullet is both copper and lead, and designed to be streamlined, the shotgun slug is all lead and very squat, taking up less space.

The inside diameter of a 50 bmg case is actually almost exactly the same diameter of a 12 gauge shell as well.
Fair. Thankyou for the insight.
 

jordanka16

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Would there be any benefit in using full brass shotshells like they used to have in the past?
Not really, standard thickness brass shells are too wide to use slugs, because of the thickness of the shotguns chamber. You have to use thick, turned brass cases, and they cost about $10 each. With plastic cases costing about 10 to 15 cents each, and that's with a primer, there's no real reason to use brass at these pressures.

Now if you wanted to step it up in certain guns to about 35,000 psi there's an advantage to be gained from brass. Or if you just wanted them to look cool.
 

Certaindeaf

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A double ball load using the Lee .690 round ball mold is extremely common.. that's a 1,000 grain payload so you could start your searches from there regarding powders etc.
 

jordanka16

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I revised the design a little bit to give 3 lube grooves, the top groove will also work as a crimp groove if you had something to crimp it in.

Probably take a couple months to get the mold in but in the meantime I have a roundball mold on the way, which is about 600 grains, so that will give me something to play with.

weight would be 1084 grains of pure lead, probably end up right around 1000 with a good alloy.

Screenshot (9).png
 
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