How much powder in a shotgun shell?


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ChaoSS
December 9, 2009, 12:58 AM
I just finished watching a mythbusters episode where they fired a 37 pound ball 80 yards with one shotgun shell full of black powder, but they didn't say how many grains that was? Just out of curiosity, does anyone know how much powder that would be if you filled, say, a 3 inch 12 gauge shell completely full of powder?

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justashooter in pa
December 9, 2009, 02:15 AM
without doing it to find out, i would say somewhere close to 450-500 grains. this estimate based upon experience loading black powder shotgun shells for use in older doubles.

80 yards isn't far. they should try the same amount of powder in a 2 gauge with round ball (1/2 pound) if they really want to do something cool.

ChaoSS
December 9, 2009, 06:42 AM
No, it's not very far, it was an experimental shoot, they did others with more powder, I was just wondering how much that really was compared to, say, how much goes in a regular shotgun load, or my .38, or whatever.

freakshow10mm
December 9, 2009, 10:56 AM
Regular 12ga load is about 40-45 grains or so. So the previous estimate of 450-500gr is pretty close I think.

EddieNFL
December 9, 2009, 11:33 AM
Haven't loaded shotshells in a while, but I recall the charge being in the 25 to 30 grain range. That was for 12 gauge 2-3/4 shells w/ 1-1/4 oz load using Hercules powder. Can't speak of other gauges/lengths.

Galil5.56
December 9, 2009, 11:56 AM
Don't know which "F" powder they used, but I took an old style 2 3/4", 12 ga poly-formed/Riefenhauser style Wincherster shotshell with the mouth fully opened, filled it flat with GOEX 3F, and my Dillon D-Terminator says 249.6 grains.

These old WW shells have a very low base wad, and a lot of volume, and IMO would represent as large a volume dropped charge as you can find aside from perhaps an ACTIVE hull, which I have but did not use.

rcmodel
December 9, 2009, 05:54 PM
There is a huge differance between black powder and smokeless powder too.

Ever see the old guys "Shooting an Anvil"?

A fairly small amount of black power will put a 200 pound anvil into low orbit!
It wouldn't work at all with smokeless powder.


http://www.telegraph.co.uk/news/worldnews/northamerica/usa/6396886/Anvil-shooting-the-worlds-strangest-sport.html

rc

ChaoSS
December 9, 2009, 06:08 PM
Yeah, for some reason I always thought that modern smokeless powder was more powerful than the older black powder, till recently, I saw something that mentioned that the black powder was actually a bigger boom. Guess that's what you get for relying on assumptions.

Thanks for the info guys, a few hundred grains is close enough, I'm not planning on setting off a cannon myself, it was just a curiosity thing.

rcmodel
December 9, 2009, 06:11 PM
Smokeless powder is more powerful.

Thats why it doesn't take as much of it to reach much higher velocity then you can get with black powder.

The difference is that smokeless powder burns and gradually builds up pressure.
Black powder just basically explodes.

rc

ChaoSS
December 9, 2009, 06:21 PM
Ok, that makes sense then.

ljnowell
December 9, 2009, 06:40 PM
Smokeless powder is more powerful.

Thats why it doesn't take as much of it to reach much higher velocity then you can get with black powder.

The difference is that smokeless powder burns and gradually builds up pressure.
Black powder just basically explodes.

rc

It was always explained this way to me too, "Smokeless powder is a propellant, black powder is an explosive."

rcmodel
December 9, 2009, 06:43 PM
Well, black powder doesn't really detonate or explode either, unless it is tightly confined.

It just burns awful fast!

As an example, primers explode.
Powders burn.
Some way faster then others is all.

rc

atblis
December 9, 2009, 06:56 PM
I think blackpowder has a lot deadweight in it. Not very energy dense.

ChaoSS
December 9, 2009, 07:35 PM
While I'm in stupid question mode.....

Does that mean that on a black powder gun the barrel length has less of an effect on speed? I know the gasses keep pushing the bullet down the barrel whether anything is burning or not, but do smokeless powders keep burning out the end of the barrel more than black powder, making the barrel length have more of an effect on the velocity?

(hope that makes sense what I'm trying to ask)

rcmodel
December 10, 2009, 02:55 PM
As already noted, black powder burns so fast it seems like it explodes.
As such, it gets it over with almost instantly and no longer produces any more gas.

Smokeless powder burn rate can be adjusted from very fast to very slow during manufacture.
So the powder correct burn rate can be selected for the cartridge in question.
It all burns in or very close to the chamber just like black powder, but it continues to generate gas pressure over a longer time period depending on the burn rate.

So in effect, black powder smacks the bullet a hard whack and is done producing pressure.
Smokeless powder continues to burn and produce expanding gas longer, and shoves the bullet all the way down the barrel.

As for barrel length?
Old time black powder rifles generally had very long barrels.
The reason is that the initial explosion blew the rest of the very large charge of BP out the muzzle of a short barrel before all of it could ignite.

This seems to contradict what we already said about black powder all going off instantly.
But when you are measuring bullet dwell time in the bore in single digit milliseconds, "instantly" takes on a different meaning.

rc

EddieNFL
December 10, 2009, 03:17 PM
Well, black powder doesn't really detonate or explode either, unless it is tightly confined.

True, but smokeless requires more confinement. I learned this trying to duplicate fireworks with granddad's Bullseye. Ain't it great being an immortal kid? All explosives have "burn rates." High and low order explosions are determined by burn rate. I think the cutoff is somewhere around 13,000 feet per second. The PETN in det cord burns at 4.5 miles per second, if memory serves. Someone correct me if my numbers are off; long time since '77.

ChaoSS
December 10, 2009, 03:23 PM
4.5 miles per second? As in, you light off one end and the other end, 4.5 miles away, goes off a second later?

EddieNFL
December 10, 2009, 03:28 PM
Yes. SGT (I've forgotten his name) explained it this way: "We could blow the colonel a new one in less than a second."

ChaoSS
December 10, 2009, 03:47 PM
That's over 20,000 fps, that's almost 20 times to speed of sound. Hot Damn....

Walkalong
December 10, 2009, 04:09 PM
The problem with smokeless powder when it was first invented was it was too powerful and too fast burning to be useful in small arms. They had to invent ways to slow it down.

rcmodel
December 10, 2009, 04:48 PM
Det cord detonates at a speed of between 7,000–8,000 m/s.
Or 4.35 to 4.97 miles per second.
Or 261 to 298 miles per minute.
Or 15,700 to 17,900 miles per hour.

All I know for sure is, don't blink or you will miss it!

That incredible speed is the difference between a controlled explosion, as in any powder charge burning, and a true detonation.

No firearm ever made could contain a true detonation.

rc

EddieNFL
December 10, 2009, 05:02 PM
All I know for sure is, don't blink or you will miss it!
Amen, brother! We used to set up a series with det cord. Very difficult to tell the first blast from the next. Fun stuff!

No firearm ever made could contain a true detonation.

I think a few have inadvertently tried...with less than optimal results.

rcmodel
December 10, 2009, 05:47 PM
Actually, short of starting that whole argument again, they haven't.

Guns blow up for a lot of reasons, but a true hypersonic shockwave detonation is not one of them.

Smokeless powder is not capable of supporting a detonation shockwave in less then warehouse or rail car quantities.

Ever try to make a bomb out of a can of smokeless powder?
Can't, because a 1 or 8 pound can of any smokeless powder simply cannot be made to detonate, even with a blasting cap & det cord to set it off.

rc

EddieNFL
December 10, 2009, 05:57 PM
Actually, short of starting that whole argument again, they haven't.

I was making a joke.

Ever try to make a bomb out of a can of smokeless powder?

Yep. Used to pour blackpowder in a shotgun hull, slip in a piece of dynamite fuse and pack paper in with a pencil. BOOM! Tried the same with Granddad's Bullseye. Fssssssssssssss.

Walkalong
December 10, 2009, 07:36 PM
Not a whole can, but yes. Works well if you can confine it well. (Think used C02 cartridges and underwater fuse) Don't be close by when it goes off. Actually, don't be anywhere near it, and preferably behind something. :what:

I wasn't always old and reasonably mature. ;)

Kernel
December 10, 2009, 08:04 PM
how much powder that would be if you filled a 3 inch 12 gauge shell completely full of powder?

The formula for volume is: height x area = h x pi x x dia^2

Of course a 3” 12 gauge shotgun shell doesn’t have an internal height of 3”. The head and the internal construction of the case takes up some of that space, say ”. Making the height 2.75”.

Volume = 2.75” x 3.14 x 0.25 x 0.729” x 0.729” = 1.15 cubic inches (in^3)

The conversion factor for cubic inches to grains is: 1 cubic inch = 252.4 grains

Therefore, a 3“ 12 gauge shotgun shell holds: 1.15 in^3 x 252.4 grains/in^3 = 290 grains

More or less.

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