Volume vs. Weight (Understanding Powder Loads for Muzzleloaders)
08-27-2014, 07:25 PM
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Boone & Crockett
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Volume vs. Weight (Understanding Powder Loads for Muzzleloaders)
VOLUME LOAD RECOMMENDATIONS
When dealing with loose powder in muzzleloaders (as opposed to preformed pellets), gun manufacturers and powder manufacturers publish their load recommendations in terms of “volume”.
For example, a manufacturer’s manual for a particular .50 caliber gun may recommend a load range of 80 to 150 grains of black powder or a black powder substitute when shooting a certain projectile - such as a 300 grain lead conical. On the other hand, a powder manufacturer addressing .50 caliber muzzleloaders in general (which includes both in-lines and sidelocks from a variety of manufacturers), may set a limit of 100 grains of their powder when shooting 300 grain lead conicals.
Well what about weight? Wouldn’t 80 grains volume be the same as 80 grains weight?
Well, yes, and no, and “it depends”. If you’re confused, don’t feel alone. Many new shooters (and some old hands) are confused by the volume vs. weight issue. I’ve seen experienced shooters tell new shooters things like “you must use a volume measure for XYZ powder”, or “never use weight, use volume charges only”. While such advice isn’t going to get the new shooter in trouble, neither is it accurate.
BACK TO THE BEGINNING: To understand the root cause of today’s volume vs. weight confusion we must go back to the original muzzleloading fuel – real black powder.
Back in the day, black powder in something approximating today’s FF granulation was pretty much the standard in rifles and shotguns. When your great great grandpappy said he was shooting 80 grains of powder he meant his powder charge actually weighed 80 grains. And he probably made a powder measure from a piece of deer antler or river cane that held that amount of powder and called it an 80 grain measure. He might even have marked it with and “80”. So originally, 80 grains volume equaled 80 grains weight.
Even with the advent of black powder cartridges such as the venerable 45-70, weight and volume were the same thing. One could reload a 45-70 cartridge with FF grade black powder using a 70 grain volume measure and the charge would weigh about 70 grains.
WHERE WE ARE TODAY: When dealing with today’s black powder substitutes such as Pyrodex, Triple Seven, Alliant Black MZ, Blackhorn 209, etc., we deal in “equivalent volume”. We still use a measure that is based on the volume and weight of black powder. However, while the volume is the same, the weight is not. With a powder measure set at 100 grains, the charge of black powder will actually weigh around 100 grains, while the same volume of Triple Seven will weigh about 78 grains. And 100 grains volume of Pyrodex will have yet a different weight, as will Blackhorn 209, and Alliant Black MZ. But for our purposes, all of them are “100 grain loads”.
SO, I CAN USE WEIGHED CHARGES? Sure you can, so long as you understand that difference between “equivalent volume” and actual weight.
The accepted way of arriving at a weighed charge is to fill you powder measure to the desired volume level, then weigh that charge and use the resulting weight as the base line for weighing out additional charges.
A WORD ABOUT VOLUMENTRIC MEASURES: In theory, today’s commercial volume measures are calibrated based on the weight/volume of FF black powder. However, they do vary. If you weigh 100 grain measures of FF black powder from three different manufacturers - say Thompson Center, CVA, and Traditions – the resulting charges will likely vary by as much as ten grains or so from high to low.
For example. I have several TC U-View measures that consistently give me 91 grains weight of GOEX FFg when set at the 100 grain mark and carefully filled without tapping or compacting.. And I have an old Lyman brass measure that produces consistent loads of around 103 grains weight when set at the 100 grain mark.
When dealing with loose powder in muzzleloaders (as opposed to preformed pellets), gun manufacturers and powder manufacturers publish their load recommendations in terms of “volume”.
For example, a manufacturer’s manual for a particular .50 caliber gun may recommend a load range of 80 to 150 grains of black powder or a black powder substitute when shooting a certain projectile - such as a 300 grain lead conical. On the other hand, a powder manufacturer addressing .50 caliber muzzleloaders in general (which includes both in-lines and sidelocks from a variety of manufacturers), may set a limit of 100 grains of their powder when shooting 300 grain lead conicals.
Well what about weight? Wouldn’t 80 grains volume be the same as 80 grains weight?
Well, yes, and no, and “it depends”. If you’re confused, don’t feel alone. Many new shooters (and some old hands) are confused by the volume vs. weight issue. I’ve seen experienced shooters tell new shooters things like “you must use a volume measure for XYZ powder”, or “never use weight, use volume charges only”. While such advice isn’t going to get the new shooter in trouble, neither is it accurate.
BACK TO THE BEGINNING: To understand the root cause of today’s volume vs. weight confusion we must go back to the original muzzleloading fuel – real black powder.
Back in the day, black powder in something approximating today’s FF granulation was pretty much the standard in rifles and shotguns. When your great great grandpappy said he was shooting 80 grains of powder he meant his powder charge actually weighed 80 grains. And he probably made a powder measure from a piece of deer antler or river cane that held that amount of powder and called it an 80 grain measure. He might even have marked it with and “80”. So originally, 80 grains volume equaled 80 grains weight.
Even with the advent of black powder cartridges such as the venerable 45-70, weight and volume were the same thing. One could reload a 45-70 cartridge with FF grade black powder using a 70 grain volume measure and the charge would weigh about 70 grains.
WHERE WE ARE TODAY: When dealing with today’s black powder substitutes such as Pyrodex, Triple Seven, Alliant Black MZ, Blackhorn 209, etc., we deal in “equivalent volume”. We still use a measure that is based on the volume and weight of black powder. However, while the volume is the same, the weight is not. With a powder measure set at 100 grains, the charge of black powder will actually weigh around 100 grains, while the same volume of Triple Seven will weigh about 78 grains. And 100 grains volume of Pyrodex will have yet a different weight, as will Blackhorn 209, and Alliant Black MZ. But for our purposes, all of them are “100 grain loads”.
SO, I CAN USE WEIGHED CHARGES? Sure you can, so long as you understand that difference between “equivalent volume” and actual weight.
The accepted way of arriving at a weighed charge is to fill you powder measure to the desired volume level, then weigh that charge and use the resulting weight as the base line for weighing out additional charges.
A WORD ABOUT VOLUMENTRIC MEASURES: In theory, today’s commercial volume measures are calibrated based on the weight/volume of FF black powder. However, they do vary. If you weigh 100 grain measures of FF black powder from three different manufacturers - say Thompson Center, CVA, and Traditions – the resulting charges will likely vary by as much as ten grains or so from high to low.
For example. I have several TC U-View measures that consistently give me 91 grains weight of GOEX FFg when set at the 100 grain mark and carefully filled without tapping or compacting.. And I have an old Lyman brass measure that produces consistent loads of around 103 grains weight when set at the 100 grain mark.
Last edited by Semisane; 12-03-2015 at 09:10 AM.
