weighing muzzleloader charges

[wileC]

pyrodex is normally measured in volume but when you get the right charge say 100gr would it not be more accurate to then weigh them? and why are the charges referred to grains when the 100gr of pyrodex (volume) actually weigh about 65 grains on a reloadinf scale??

 

[Longcruise]

Pyrodex is meant to be pretty much equivelant to Goex ffg when used in equal volume. My chrono results with show that to be pretty much the case.

In your other thread on bp, etc., I mentioned an experiment involving tapping and not tapping the measure. I found that data and it's below.

So, to kill two birds with one turd, these charges were thrown from an adjustable measure set at 100 grains. As you can see, they don't throw 100 grains by weight.

I poured 10 charges into an adjustable measure of the type with a shear off funnel on the top. The first ten charges were sheared off and weighed without tapping the measure and the next ten were poured, tapped with a flick of the finger three times and then sheared off and weighed.

93.5
94.1
93.2
92.5
92.8
93.6
94.0
92.8
93.5
92.2

93.2 Average Weight
.63 Standard Deviation
1.9 Extreme Spread


94.3
94.2
93.5
93.9
93.8
94.1
94.1
94.0
94.1
94.3

94.0 Average Weight
.25 Standard Deviation
.8 Extreme Spread

 

[pcammo]

Pyrodex is designed to be a volume equivalent to black powder. Since its' chemistry is slightly higher in energy per mass, it is engineered to a lower density.

As for weighing the charges...It really is a story of relativity. When you are shooting small, high efficiency cartridges, then a small change in propellant mass will make a difference in performance. Likewise, when you light the fire under 65 grains (by mass) of Pyrodex, a small change in powder mass will have a negligible effect. You can prove this to yourself by weighing several charges of Pyrodex, say 65 grains and fire them over a chronograph. Then weigh several charges of say 66 grains and fire them. It is unlikely you will notice a statistical difference. However in the .223 Rem. a whole grain of powder will make a big difference and indeed that grain is a higher percentage of the total mass of powder.
John