Measuring black powder charges

[Naphtali]

Several months ago, I queried about weight charges of black powder. Many responders informed me that black powder loads are measured by volume, not by weight.

What has occurred to me is the question: How is a powder measure calibrated to yield correct volume in grains?

[Natureboy]

  And which grains are used in the calibration, barley or wheat?  Summer or winter? 

[snapper]

depending on what type of shooter you are it might work just perfect to use a volume measure.

If you have a scale, you can check to see if your volume measure is throwing the right amount of powder by weight.

However, if you have a good load and it works for you, who cares?

I weigh most of my powder to the tenth of a grain.  But I am playing in a different ML game than what most people do.

Fleener

[Eric Krewson]

I shot all kinds of combinations a few days ago. #6, #4, lots of powder, less powder, lots of shot and less shot. I even patched the shot but found it didn’t work worth a hoot in a jug choke.

Sometimes I weighed my components, sometimes I used a powder measure.

I noticed when I weighed my powder my pattern opened up a good bit so I checked my powder measure and found when it was set on 100 gr it was really throwing 85 with 1F.

My best patterns were with 85 gr of 1F and 1 ¼ oz of shot, 7 to the spine of a turkey target at 25 yards.

[T*O*F]

How is a powder measure calibrated to yield correct volume in grains?

Powders differ in granulation size and density between brands.  I think I heard once that most measures are calibrated using Goex 2F.  Using 3F would yield a heavier volume as would Swiss 2F since it is more dense.

You should fire your rifle to find its best load.  Then weigh the load and calibrate a fixed measure that throws that load.  Fixed measure tubes are available that can be cut down to the desired size.  Then dedicate that measure to that gun.  That being said, different batches of the same powder can vary.

Adjustable measures work entirely on thrown volume loads regardless of  weight differences between powders.  These are things you should be able to figure out on your own instead of relying on the experiences of others who are not in your same situation.    It's called load development and the type of tube used to dump it down the barrel is really irrelevant.

[D. Taylor Sapergia]

TOF:  sound advice!!

[Mike_StL]

Powder measures are calibrated for a specific grain weight for a particular granulation.  Most of my measures seem to have been calibrated for 2fg GOEX.  I get about 5 to 8% more grain weight with 3fg powders.  The weight is based on 7000 grains to the pound.

[Daryl]

Although I have an adjustable measure for use when testing loads, once I find the accuracy load for a rifle, I weigh the powder the measure throws at that setting.  Then, I make a powder measure throwing THAT amount of powder out of range salvage ctg. brass, with a soldered in screw-eye for the thong to attach to the possible's bag or horn I use with THAT gun. I mark the measure with a felt pen - or notches to correspond to the dram measure that the powder measure throws.

[Arcturus]

  And which grains are used in the calibration, barley or wheat?  Summer or winter? 

One English pound was decreed long ago to equal 7000 plump grains of WHEAT.   

[David R. Pennington]

I always work up the best load for the rifle by starting at or just above caliber with same charge and work up 5 grains at a time till I get the best groups and back down when the groups start to open back up. I use the same graduated adjustable measure for the whole process so for my practical application the accuracy of weight is immaterial. I guess it might be a good idea to weigh it and record the actual weight of the optimal charge in case I ever changed or lost my measure.
I have a piece of horn tip attached to my hunting bag that I have learned to load 3 different rifles with. Level full it throws 65 grains, heaping full it throws 75 grains and just shy of full 55 grains.

[Daryl]

I guess it might be a good idea to weigh it and record the actual weight of the optimal charge in case I ever changed or lost my measure.

Exactly!

[smylee grouch]

I have one of those home made horn tips hallowed out to hold 55 gr. of 2f. Been using it since 1969 IIRC. weighing and recording is a good idea in case you do lose the adjustable measure or change powder brands,or sizes.

[Daryl]

A 3/8" top opening of the powder measure will throw MUCH more accurate charges than a measure made from horn, bone or antler. An antler charger I have, will vary over 5gr. lightest to heaviest, all thrown from the same horn, same technique into the measure.

My smaller measures, from 1/4" to .4", throw charges that rarely vary more than 1 gr. using the same horns and technique. I or even 3 grains of powder will normally not change ANYTHING as to accuracy in a black powder rifle.  I would not bet on 5 grains not changing accuracy.  So - if interested in consistency, use a smaller diameter measure. Remember, consistency is 50% of your accuracy with a black powder rifle.

[smylee grouch]

I just bought a 100-200 gr. adjustable measure at the WNS in Pheonix to use with a light bench gun. Looks like a sewer pipe compared to my other measures. Have not used it yet or checked it out compared to my other measures.

[Daryl]

If the measure is a large diameter, you might get more accurate results if using a horn or spout on a can with a small, .22 cal sized opening, so the powder dribbles out at the same speed every time when held at the same angle.  I would then scrape off the top of the measure with a straight tool, back of a knife or whatever and test weigh a bunch of 'throws' to see what the consistency was like.
This is just a thought as much of that game is exact consistency, shot to shot.