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What volume is one "volumetric grain" of BP ?

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16 January 2003, 01:58
Jiri
What volume is one "volumetric grain" of BP ?
...load is 35 volumetric grains of BP, every BP has a different density, BP equivalents too, so if I know density of BP, a could count a weight but I need to know this volume too . . .

Thank you, Jiri
16 January 2003, 07:40
The Dane
Weigh the load, and use as is! BP weighs roughly the same as water, so 1 cc of BP weighs @14,5 grains. BP is so low powered a propellant that a grain more or less dont show on a chronograph.
I tested a volume measure once, and set at 100 grains it threw loads from 98-101 grains (weighed)with anything fron 1F to 4F.

[ 01-16-2003, 00:30: Message edited by: The Dane ]
17 January 2003, 03:05
Jiri
Ok, I understand volumetric grain could be volume of grain of water, so if BP equivalent has a density for example 0.6 g/cm^3, I will put there 0.6/1*35 so it is 21 grain of BP equivalent, volume will be the same and because it is volume to volume equivalent, it will be ok . . .

Thanks

Jiri
17 January 2003, 11:51
Tailgunner
Jiri
True black powders weigh and measure (for all practial purposes) the same (grain/grain).
It's the substitute blacks (like Pyrodex) that can get you in trouble with weight. Pyrodex is as bulky (volume) as true black, but weighs less (per volume) so the grain weight is less for the equivalent Pyrodex charge.
17 January 2003, 22:43
Jiri
Tailgunner:

This is exactly what I sad, Pyrodex is softer (less density), for example 0.6, black powder is 1 (in metric units g/cm^3), so volumetric load for BP is 35, weight load for pyrodex will be (0.6/1)x35=21 grain . . .