# Grain to Gram conversion

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#### xenon

##### Well-Known Member
does anyone have a chart with the conversion from grains to grams for black powder?

thanks

One gram = 15.4323584 grain

steve

One grain is approximately 0.0648 grams.
or
One gram is approximately 15.43 grains.

Weight is weight. A grain of BP weighs the same as a grain of pyrodex.

Hmm. In your previous post did you mean grain as in unit of weight, or grain as in "one single piece" of BP? My answer assumed you meant unit of weight. If you didn't mean that, please disregard my answer.

Mine as well.

steve

I think I meant the unit of weight. I just bought a new powder measure that measures 5-50 grains of powder, so I would assume I meant weight, but it measures in volume.
With the Pyrodex, I was thinking it might have a slightly different density than BP, kind of like the difference between 4f and 3f

So the 15.43 is 4f right? what is 3f then?

Sorry, should have asked in the first place

Originally posted by xenon
I think I meant the unit of weight. I just bought a new powder measure that measures 5-50 grains of powder, so I would assume I meant weight, but it measures in volume.
With the Pyrodex, I was thinking it might have a slightly different density than BP, kind of like the difference between 4f and 3f

So the 15.43 is 4f right? what is 3f then?

Sorry, should have asked in the first place

Like I said, grains is normally used as a unit of weight, but I agree, your scoop is obviously measuring volume, and must be calibrated for BP. I'm afraid I don't know the relative weight of given volumes of BP and Pyrodex, so I can't help.

Maybe they're the same? I don't know.

but a lot smaller. one grain of BP weighs the same as one grain of flour, though one particle of BP weighs a different amount than one particle of flour.

15.4 grains of BP weighs the same as 15.4 grains of water, just like one gram of BP weighs the same as one gram of water, or feathers, or lead.

the term grains does NOT denote particles, but mass instead.

hope this helps.

Yeah, but xenon's question is really "how much pyrodex do I have in this volumetric measure if it says it contains x grains of BP". At least I think that's what the question is?

Originally posted by xenon
I think I meant the unit of weight. I just bought a new powder measure that measures 5-50 grains of powder, so I would assume I meant weight, but it measures in volume.
With the Pyrodex, I was thinking it might have a slightly different density than BP, kind of like the difference between 4f and 3f

So the 15.43 is 4f right? what is 3f then?

Sorry, should have asked in the first place

OK, you've got a volume measure calibrated to BP by density.

Figure out what that volume is (for X number of grains)-- measure it, in millimeters. You'll need some volume calculation formulae; cylinder = hieght * area (pi r squared); hemisphere = 4/3 pi r cubed divided by two; cylinder with hemisphere bottom is an addition of the two parts.

You'll have X grains per Y cubic millimeters.

Convert that to 1000 cubic millimeters (one cubic centimeter): 1000 divided by your measured volume = your conversion factor.

Multiply your number of grains in that measured volume times your conversion factor, and you'll have grains per cubic centimeter.

Convert that to grams by dividing grains by 15.34 and you'll have the density of BP in g/cc, the standard density measure.

Pyrodex is 0.75 g/cc. Now you can make a ratio comparison: 0.75 divided by density of BP = density of pyrodex in terms of BP density. Now you can meaure pyrodex with your spoon, and when the spoon says Z grains, multiply that Z times this conversion factor to get grains of pyrodex.

I got the density of pyrodex from its Material Safety Data Sheet. I couldn't find one for BP. If you can find an MSDS for BP, no need to calculate anything except in comparing the two; you can get the Z ratio factor in the last step here right from those.

okay, thanks for all the replys.

I know 4f bp is 1g/cc so we have the conversion factor of
1.3333, right?

I guess I know everything I need to know, exept weather it measures 2f 3f or 4f because the densities are different, I guess I'll have to measure the volume then

Originally posted by hokkyokusei
Weight is weight. .

ummm , mass is mass. Weight depends on gravity. I.E. you weigh approximately 1/6 on the moon as you do on earth. Your mass is the same in both places.

Originally posted by seo
ummm , mass is mass. Weight depends on gravity. I.E. you weigh approximately 1/6 on the moon as you do on earth. Your mass is the same in both places.

Pardon me, I assumed he was measuring his BP and Pyrodex on the Earth.

Originally posted by hokkyokusei
Pardon me, I assumed he was measuring his BP and Pyrodex on the Earth.

Didn't mean to offend, please accept my apologies. My response was nitpicky and I am sorry.

Probably a flashback from my days at college. :kill: We always had to differentiate pounds mass (aka slugs) from pounds weight. Unfortunately here in the U.S., we still follow the english system where pound is used both for mass and weight. This thread has been talking about grams and grains which are both mass units in the metric system, so my comments were not really needed.

No problem.

Originally posted by xenon
okay, thanks for all the replys.

I know 4f bp is 1g/cc so we have the conversion factor of
1.3333, right?

That would be for starting with pyrodex and converting to BP.

Pyrodex = 0.75 the density of BP. Measure with your BP spoon and multiply by 0.75 to get pyrodex weight.

I frankly don't know what the Xf stands for in BP. If it has something to do with the granularity, that's fine, because they're taking the air in the spaces between the granules into account.

Yes, 4f is the usual used in rocketry, 3f gets some use and is less fine. The problem is that it says it measures "black powder" but since a grain is a weight measurement and 3f and 4f are different weights, which one is it?

Originally posted by xenon
Yes, 4f is the usual used in rocketry, 3f gets some use and is less fine. The problem is that it says it measures "black powder" but since a grain is a weight measurement and 3f and 4f are different weights, which one is it?

I doubt it matters. The difference between what's probably "fine" and "very fine" will be very small if what they're made of is the same substance. The difference between any granulated BP and pyrodex would be far greater than between different granularities of BP.

I am not a black-powder shooter---all I know about FF or FFF or FFFFFFFFFF is that one is ground more finely than the other.

I am a shooter of several rifle and pistol cartridges, and a reloader of same. As far as what difference it makes to measure a charge to be used in a firearm, the difference is potentially quite significant. If you are just shooting run-of-the-mill target or practice loads, a volumetric ("scoop") measurement of weight might be close enough as long as you use the measure consistently. If you are working up to the extreme limit of what your firearm/cartridge/bullet will deliver ballistically, then the difference can be critical. An extra grain (or even fraction of a grain) can cause case neck or head separation, or damage to the action (mechanical components that operate the firing chamber) of the gun.

When reloading for firearms I never use scoops. Pay the whopping \$10 or \$20 to find a decent powder weight scale (I got my last one on ebay for \$5). They will generally weigh accurately down to 1/10th of a grain---that is 1/70000th of a pound, or about 7 milligrams.

And we all do our work to that level of accuracy, don't we?

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