Big Shotgun of Enormous Doom

[Nolo]

Okay, I'm trying to design a more powerful combat shotgun. A normal 12-gauge shoots about eight 000 buckshot balls. I want to increase the capacity of 000 in my shotgun to about 16-24 000 buckshot balls. Which is alot. I know. And I know that is probably an unrealistic setup. I know. But I have my reasons for wanting such an unrealistic system, so bear with me.
Anyway, I started with the 40mm M79's canister loads (of buckshot, I forget their designation), and I worked from there. What I've come up with is a 40x45mm buckshot load, and I was wondering: for a cartridge of that size, do you think it would be better to have a rimmed or rimless case?
By the way, the shotgun is a semiauto, so think about that when you answer.

 

[ArmedBear]

Sounds like a golldurn pea-shooter. Get a REAL gun, with a REAL load in it.

Video of one being fired: http://www.youtube.com/watch?v=-kdG2dwNb60

 

[Avenger29]

16-24 00 buckshot balls.

Well, the 3" shells typically load 15 00 pellets. I have no idea how much the 3.5" shells load.

 

[Owen]

ouch

 

[Nolo]

No, it's not 00, it's 000. Triple-ought. My error.

 

[Nolo]

And I was still wondering whether it would be better to use a rimmed or rimless design. I should mention it feeds from a tubular magazine.

 

[Cosmoline]

It will probably make things easier if you make it rimmed. Assuming your action is some upsized version of an existing semiauto, you can just make a bigger version of a shotgun shell. And you'll probably find function and maintenance a lot better and easier with the rim on. Rimless has some advantages for magazine feeding firearms, but all the really big boomers I can think of use rimmed. Certainly it's a natural fit for a tube magazine.

 

[Nolo]

That's good.
It basically is an upscaled semiauto (actually heavily based on the Auto-5), but the round is of significantly different dimensions. It is short and fat (like I said, 40x45mm), to aid with patterning and allow a higher tubular magazine capacity.

 

[Nolo]

It's now 38x45mm.

 

[Cosmoline]

If you don't have a rim you're going to have to headspace on the shoulder or the lip or some kind of band, and I suspect that would be tricky with a squat cartridge like that.

 

[Nolo]

Rim it is, then!

 

[jonjon1885]

soooo.... you haven't yet told why you wish to punish your self yet with such a punishing sounding load

 

[rkh]

^^

I seriously suggest you try firing some 12 gauge magnums before you waste your money. A gun that's painful to shoot is not one that you will adequately practice with.

 

[Nolo]

Waste what money?
Who said I was going to spend any money?
I have fired 12 Gauge Magnum loads (3 and 1/2 inch, 00 buck), and they hurt, if I fire them enough. I think I've also fired a 10 Gauge, but I'm not sure, it could've been a 12, 3.5 inch.
As for why I am doing this, I haven't told you for a good reason. Nothing stupid, like I don't want anyone stealing my ideas (anybody can come up with an oversized shotgun!), but there's a good reason.

 

[Jorg Nysgerrig]

I have a feeling this is going to be like your "perfect" rifle cartridge you shared in Rifle Country that had amazing ballistics, but the chamber pressure exceeded the yield strength of most steel alloys.

A 38mm bore would be larger than a 1 1/2 gauge. 24 000 pellets would weigh 1632 grains, more than double the weight of a .50 BMG slug.

 

[Nolo]

No, I think I've fixed everything with this one. It's essentially the same concept as the M79 Buckshot round. And I'm going for a very specific goal here, and I care much less about size.
Besides, we did actually get the perfect cartridge in Rifle Country. This is an entirely different animal.
Plus, I'm not trying to push that lead at 3,200 fps (like a .50 BMG), I'm going for normal shotgun speeds (and speed is easier to obtain the larger you get, learned that in my UCR thread, too), i.e. 800-1200 f/s. More on the 800 f/s side. The shot doesn't have to go more than about 30 yards.

 

[Nolo]

Here it is, all finalized and sparkley:

If anyone has a pictures of the M576 buckshot round in cross-section, I'd really appreciate a look at it. They figured out how to get good pressure, and I want to be sure my round has the proper pressures.

 

[2TransAms]

Uh...are you designing this round with MS Paint?

Kidding aside,are you just designing specs for this shotgun or are you actually going to build it?

 

[Nolo]

And, just for sheizes and gekickers, here's the round in a real-life color scheme (note the aluminum hull):


Yes, I designed this round with MS Paint, it's really the only thing I use to render rounds. First I draw them with pencil and paper, then I take the specifications and create them in Paint.
And, if I ever get the chance, yes, I will build this shotgun. But I fear the chance will be quite a ways off...

 

[Deer Hunter]

Don't get discouraged. I never thought I would build my double barrel pump action dream shotgun, but it's leaning against the wall in my room as I speak, ready to get a forend designed and attatched to it.

Go for it. When you strip away all the serious issues that firearm ownership places on its owner's shoulders, all the politics, tactics, and training, you're left with one indisputable fact: Boomsticks are fun as hell. And in your (and mine as well) case, they're even more fun when you dream of it yourself.

 

[Nolo]

Oh, man.
You have a double-barreled pump?
Do you have a picture of it?
I once designed a double-barreled automatic (and I mean automatic) just because I could.
It was an 8-gauge, blowback monster that fed from a split drum (one half of the circle fed one barrel, the other half fed the other). It would've worked, too. Well, I'm not sure anyone could have fired it without a tripod, but it would have mechanically worked.
I designed it for the sole purpose of filling the air in front of it with lead.
I called it the Cornpop Raccoon. It's sort of an inside joke between my friends and I.

 

[Nolo]

I think this version of the round would work better, it takes more from the M576:

 

[Deer Hunter]

http://thehighroad.org/showthread.php?t=280902

It's not done all the way, as I have a different LH barrel on the way and I'm still in the process of ordering the material (louisville slugger) for the forend and I need to do a little work to the buttstock, but that's it in a very crude (but functional) form.

 

[Nolo]

Interesting.
Alot less ugly than I was expecting.
Still an ugly baby, though.
But I love it all the same.
I'd have combined the receivers if I had the machinery. And I'd have made it have a double trigger assembly (like a real SxS), and I think I figured out a way to have the forend work.
Either use a vertical forend or you could take one of the ribbed Mossberg forends (a couple of other shotguns have them too) and shaved it down and attached it. I'm not sure that'd give you positive control, though.

 

[Deer Hunter]

You'd be sacrificing the strength of those forends by trying to saw them up and make them fit. That's why I'm fabricating my own. And any attempt to attatch the receivers internally would sacrifice the strength of them, which I didn't want to do. You gotta take the good with the bad sometimes.

Now get this thread back on topic, it's your thread, not mine.