practical smokeless loads

Hi All,
I am a newbie here, as well as a newbie to muzzle loading. I?ve had a muzzle loader for years and have used it for hunting ML special seasons but really never ?got into it? that much.

For years I?ve shot center-fire and reload all my own ammunition, so I?m pretty knowledgeable about loads, pressures, practices, etc.

What I?m struggling with is the reasons why a smokeless powder can?t be substituted for black powder.

Why would it be dangerous to use a load of 50grs of IMR4198 with a 250gr flat base bullet in a plastic sabot in a 50cal 1:28 twist muzzleloading rifle?

Would such a load exceed the pressures of a typical 150grs ff BP load?

How can the saboted shot gun loads use smokeless safely? Why couldn?t a load like 35grs of IMR SR 4756 and a 250gr saboted bullet be safe?

What am I missing here?

Thanks for any insight for you experienced guys can offer.

If you do not have a muzzleloader designed for smokeless the barrels may not withstand the pressure and blow up.
I would think 35 gr. of 4756 would be very high pressure load even for a smokeless barrel.

I can't see how the nearly 0.250" wall of a ML barrel is that much weaker then the 0.060" wall of a 20ga shot gun. 32grs of IMR SR 4756 and a 300gr saboted slug is pretty typical for a 20ga rifled shotgun. Velocity of such a load is in the 1600fps. Only real difference is there is a good amount more volume in the 20ga barrel to fill.

I still don't get it.......

Its not only the barrel but a combination of all the design factors. Thats why when you see a T/C or H&R 45/70 conversion, they are not just using a OEM T/C plug. They are normally using a Savage, PA Petes or a SMI breach plug which have all been well tested.

There are also other factors with the powder than just how fast it burns. Some grains are too small and will get through the flash hole. IMR4756 is listed as a fine grain. Is it a ball powder? Its also listed as being VERY fast compared to normally used SML powders.

BTW this site and its admins do not condone topics about using smokeless in non approved platforms. Suggesting or asking about a specific smokeless load in a non approved platform might get edited or deleted.

http://www.modernmuzzleloader.com/phpBB ... c.php?t=24

Thanks for your response

I am not asking or considering using smokeless in an unapproved application. The question is why can smokeless powder be used in similar applications with similar or lesser construction safely. (e.g. shot gun slugs). I can totally understand the grain size issue.

If this is not the appropriate place of such a topic, please forgive me and remove the thread.

Now, the answer to your question. . .
Difference between smokeless gun and non-smokeless gun.

Black Powder and Black Powder substitutes have a extremely low burn rate compared to smokeless powder.

What this means is, When black powder is set off, it ignites very slowly. Because of the slower burn, the pressure in the barrel increases much much slower than with smokeless powder. this also means your projectile will start moving towards your muzzle end, long before the pressure in your barrel becomes to great to burst your barrel.

Incomes smokeless powder. . .It has an extremely FAST burn rate. When it is ignited inside the barrel, it builds up pressure so fast, that the projectile doesn't even get a chance to move out of the barrel before the barrel reaches its bursting point from the powder. Thus, you have a perfect pipe bomb that is more than willing to go off.

Smokeless puts a HIGH amount of pressure inside that barrel in such a short amount of time, most barrels cannot handle that.

Black Powder puts pressure in that barrel too, but it does it MUCH slower, and by the time black powder builds up any kind of pressure to even look at, your projectile has already left the barrel, and the excess pressure is leaving out of the barrel too.

I think there is a better way to explain this.

Not all SMLs are even designed to use the same powders. BigDawg or BadBull IIRC only recommends 4350. SMI's load data is a little different than Savage load data and they are quite often more accurate when you use SMI's load data. Only two powders are actually recommended in my NULA but a few others appear to be safe in mine.

You dont load a random powder in a Shotshell only because its possible it can make the same PEAK pressure as a recommended load of powder....correct?

You dont down load FFFFG pan powder instead of FFFG in a 50cal ML...probably not.

BTW the 4198 load you mentioned would NOT be reliable even in a Savage 50cal. You would need far more powder to create enough pressure to be reliable.

This stuff is not rocket science. If you can measure the rise time and duration of the pressure curve of a max BP sub load in your rifle and you have a good working knowledge of internal ballistics, you can create a smokeless load that will be safe in your gun. This does not mean its safe in anyone else's gun. If you have to ask for instructions from anyone on what to do, I would say you are already in the danger zone.

It seems pretty clear that the major difference is the pressure curve between smokeless and BP. Makes sense why traditional BP rifles have such long barrels (a=f/m). Increase the time constant (t^2) that "f" is present, increase the "a" by the square.

So what is needed is a nitro based powder that has a burn rate similar to BP. I'll do some research on powder burn rates.

Thanks

adrexco said:

It seems pretty clear that the major difference is the pressure curve between smokeless and BP. Makes sense why traditional BP rifles have such long barrels (a=f/m). Increase the time constant (t^2) that "f" is present, increase the "a" by the square.

So what is needed is a nitro based powder that has a burn rate similar to BP. I'll do some research on powder burn rates.

Thanks

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That is correct. . . .

If I remember correctly, BlackHorn 209 is one of those powders. . .

Only problem with Nitro based powders. . .. You need extremely good containment at the beginning. . ..That is why most people who shoot BH209 shoot Sabots. . .

Though I have never shot BH209. . .lots of people swear by it. . .

All my guns shoot Black Powder or its substitute. . . Flintlocks and percussions like this stuff. . .

It seems IMR 3031 has a similar burn rate to BP and about the closest mass. It seems to approximate BH209 by mass.

Anyone know how it measures by volume? Is this powder recommended in any SMI approved systems?

It is also a recommended powder for period 45/70 arms originally developed for BP.

What dynamics occur with plastic sabots vs. metallic contact? There must be some factors to consider with this.

Thanks everyone for entertaining my neophyte questions!

adrexco said:

It seems IMR 3031 has a similar burn rate to BP and about the closest mass. It seems to approximate BH209 by mass.

Anyone know how it measures by volume? Is this powder recommended in any SMI approved systems?

It is also a recommended powder for period 45/70 arms originally developed for BP.

What dynamics occur with plastic sabots vs. metallic contact? There must be some factors to consider with this.

Thanks everyone for entertaining my neophyte questions!

Click to expand...

Burn rate is not the only factor. . .. The most important factor is burn rate UNDER PRESSURE.

Black Powder will outburn Nitro based powder 10 to 1 in normal atmospheric conditions. But Nitro will outburn Black Powder in Pressurized atmosphere.

Because of this, Nitro based powders are dangerous for those who attempt to use it in regular barrels as a powder. The burn rate is so darn high in pressurized barrel, and increases tremendously compared to Black Powder under the same pressure.

the biggest reason why people use Sabots with Nitro based powder, is the containment. They need enough containment to ignite and KEEP the Nito based powder ignited for a complete burn. Conicals and PRB for the most part, do not have enough containment pressure for a complete burn of Nitro.

Black Power is easily ignited under little to no pressure. The chemical reaction is not as violent as Nitro, nor does it take as much pressure to keep it going. Thus, if you want a SURE ignition with any gun, Black Powder is the way to go.

Actually, 25k psi from BP is the same pressure as 25k psi from smokeless.

I've read quite a few accounts that barrel material is the limiting factor. Sorry but I don't believe this is a valid point.

Surely there are Nitro based powders that will far exceed the pressures of BP. Certainly there are steel alloys and heat treating processes that must be employed for barrels designed for pressures in the 50kpsi and greater.

This is not the case for firearms initially designed for black powder. Loads such as 50grs of IMR4198 in a .45 cal barrel will only reach about 18k psi pressure (based on published 45-70 load data).

I'm starting to think more on the lack to build pressure due to the sabot is more of an issue. As mentioned above smokeless needs much higher pressures to burn at an explosive rate.

While you are getting close in your thinking, you also need to account for no gap between the powder and the bullet. There are pressure traces on the net of a 50 gr of H4198 and a 195 gr Barnes averaging 24k psi in a .45 cal ML barrel.

What pressure does a BP sub load create? A 120 gr by volume load of BH209 will create ~ 22k psi. A 150 gr by volume load of BH209 will create ~26k psi.

I am not saying a 50 gr H4198 in a standard ML is safe by any means.

I will do some more research on powders with burn rates and volume density similar to BP. I will also see if there is any data on published 45 cal compressed loads (doubtful).

lot of pressure tracings on doug's

Re:

adrexco said:

I've read quite a few accounts that barrel material is the limiting factor. Sorry but I don't believe this is a valid point.

Click to expand...

You are very wronged in dis thinkin. Dem originaled ML had iron barrels and den mixed steel as like dat Damascus stuff. Dey could hold prodigious dump of de "holy black" wif no trouble. Dey would be like thet aforementioned pipe bomb if use smokeless in them. dat even applies to olden paper and brass cartridge guns like trapdoors, 73 winnys and original Sharps and rollers. Dere are people that build ML today jus like historical. Grandpa even showed us boys years ago how to build a duck/goose punter gun out of steampipe. Dem for BP only for sure. Like whenever guns are involved it's safety first! Sorta like having some powder/cartridges/loads etc... and you aint sured of what kinds it's "when in doubt dump it out"!

Stay hidden and stay safe!

W

I love grown ups who talk like children.

Dwayne said:

Burn rate is not the only factor. . .. The most important factor is burn rate UNDER PRESSURE.

Black Powder will outburn Nitro based powder 10 to 1 in normal atmospheric conditions. But Nitro will outburn Black Powder in Pressurized atmosphere.

Because of this, Nitro based powders are dangerous for those who attempt to use it in regular barrels as a powder. The burn rate is so darn high in pressurized barrel, and increases tremendously compared to Black Powder under the same pressure.

the biggest reason why people use Sabots with Nitro based powder, is the containment. They need enough containment to ignite and KEEP the Nito based powder ignited for a complete burn. Conicals and PRB for the most part, do not have enough containment pressure for a complete burn of Nitro.

Black Power is easily ignited under little to no pressure. The chemical reaction is not as violent as Nitro, nor does it take as much pressure to keep it going. Thus, if you want a SURE ignition with any gun, Black Powder is the way to go.

Click to expand...

Smokeless in any percussion or flintlock is a hand grenade with the pin pulled.!!! There is so much more energy released by smokeless powder that it can’t be controlled or held by cap or flint ignition