500gr powder measure

[Terry C.]

Here is my new 500 grain black powder measure.

This was an interesting project, not only for the end result but also for a lesson in assumptions.

I built this from the leftover end of a copper "air chamber" that I used to make my powder ladle. These are available at Lowe's (where I bought mine) and other stores that sell plumbing supplies. The scoop portion is cut from the closed end of the chamber and has a brass ¼" nut soldered on the side.

The handle is a Nicholson 'Type C' file handle. This handle has a pilot hole that is the perfect size for a solid brass 'toilet screw'. The toilet screw has a wood screw thread on one end and a ¼x20 machine screw thread on the other. These are inexpensive and readily available, and I used several of them in building my field carriage. The toilet screw is threaded into the handle leaving just enough of the machine screw thread sticking out to allow the brass jam nut to turn and lock the handle to the scoop.

The handle is very attractive as-is, but I may try to stain it darker later. Haven't decided yet.


Now for the lesson.

I built this using my Cabelas EG1500 electronic scale to calibrate the scoop. This measure is calibrated for 500 grains of Goex Fg.

I had always heard, and just assumed to be true, that when measured by volume, a charge of FFg would weigh more than a charge of coarser Fg. This is also born out by the chart that came with my Lee powder scoop set. It shows across the board, higher weights from each scoop with FFg as opposed to Fg.

However, this proved NOT to be the case! I just recently placed a powder order, so I had several cans of both grades to verify that the first weigh-in was not a fluke. All of the cans of FFg threw lighter charges from the measure than any of the cans of Fg.

The measure throws an accurate 500 grain Fg charge, but a throw of FFg from this measure averages only 479 grains.


Shown in the last photo is all of the ingredients for another measure. Copper chamber, file handle, brass toilet screws, and brass nuts. All of this totals less than ten bucks. I'm going to make a complete 250 grain Fg measure (for ball shooting).

Then I may get another chamber ($3.38) and make a scoop that throws an accurate 500 grain FFg charge. Depends on whether or not I can tell the difference in the reduced FFg blank charge. (update: I no longer use FFg in this cannon)

[Terry C.]

Oops, almost forgot!  :-D

[Cpt Ed]

Nice job Terry C, thanks for adding the Goex can for size.

We would like to see you bring your fine cannon to Brooksville, Florida, the Hernando Sportsman ClubÂ’s Range for our December 11th, 2005
Live Cannon and Mortar Shoot.



Link to Hernando Sportsman ClubÂ’s web site, search calendar and events for the cannon shoot. http://www.hernandosportsmansclub.com/

[Powder keg]

Great idea for a large powder scoop. Thanks for the pictures!!!

[Double D]

So what about measurements of FG in GOEX, WANO, SWISS, and SCHUETZEN in your measure?

[Terry C.]

So what about measurements of FG in GOEX, WANO, SWISS, and SCHUETZEN in your measure?

I got any powder you want, as long as it's Goex.


I currently have about twelve pounds of Goex powder in four grades (Fg, FFg, FFFg, FFFFg).  That might not sound like much to some of you, but for me it represents a significant investment of my increasingly scarce 'disposable' income. Since I have no real plans to use anything else, my measure was made for Goex.


As a matter of fact, before I started I e-mailed Goex to see if there was some industry standard by which the volume measures are made.

Their reply was that there was not any standard that they knew of, and my plan to use the scale to calibrate the measure was, in their opinion, the best way to proceed.


I was expecting that the weight would be different for Fg and FFg, what I was NOT expecting was that the FFg would yield lighter charge weights. This flies in the face of everything I've read or been told, the FFg should weigh more than the Fg.


I would be very interested in hearing from anyone else who can replicate this experiment with other powders (or even other lots of Goex).

Anyone else use an electronic scale, with both Fg and FFg powders?

[Terry C.]

I just finished the 250 grain Fg measure.

The copper needs a little more cleanup, but here it is next to its big sister:

[Cat Whisperer]

The larger grains take up more space - bigger (relatively) spaces inbetween.  This is consistant with sizing of rock for heat storage from solar collectors - you have to get up to a 2-1/2" or a little bigger rock before the airflow around them works well.


Good lookin' scoops dude!

[pyro_tek]

These look great. Any plans on marking them with the measured weight/grade of powder?

[Terry C.]

Yes, I'm going to stamp them eventually, when (if?) I find my numeric stamps. I have my letters, but the numbers have went amiss.


CW, I understand what you are saying but that would seem to support the argument that the finer grains would pack more tightly into the measure.

I've had it drilled into my head that an equal volume of FFg will weigh more than the same volume of Fg.

That was supported by the chart that came with the Lee dippers. All of the dippers are shown to dispense a higher weight of FFg than Fg.


But my measures do not.

It can't be a matter of a specific lot since I have tried powder from two different orders placed a year apart.

The result was the same. The measures throw a higher weight of Fg than FFg.

As I look back, that's probably why all of my store-bought measures have seemed so innacurate. I would generally be using these small measures with FFg powder, and they would all throw much lighter than the marked charge.

[Terry C.]

Finally got back to this.

First I had to order a new set of numeric stamps, as my old set grew legs.

Then I had to figure out how to stamp the measures without distorting them.

For this, I built a quick & dirty "anvil" out of an old bolt and a piece of scrap angle.

The angle stock is 3" x 5" x 1/2". The bolt is a heat treated 7/8" master link bolt for a CAT bulldozer. I chose this bolt partly because it's extremely hard but mostly because it has a shoulder that is slghtly oversized compared to a standard bolt, and is a better fit inside the copper measure.




I cut a 3" wide section of the angle for the base. The edge of the 5" flange was ragged, and it didn't really need to be that long. Instead of just lopping it off square, I laid out a radius on that edge. The base is now four inches at the widest point.

I then burned a hole in the three inch flange for the bolt to pass through. The threaded section of the bolt was cut off and the end rounded. The head of the bolt is welded to the angle. The corners were cut away following the shape of the hex head.

It's not pretty (I was in a hurry) but it's solid as the proverbial rock.




The bolt is not a tight fit, but it doesn't have to be. It's close enough to the ID that it supports the copper and the stamps don't distort the measure.

So now my custom measures finally have weight and granulation markings.

[Cat Whisperer]

Quality, dude, quality.

Now you need a hall-mark to identiy it as your copper-smithing.

[Powder keg]

Very Nice!!!

[pyro_tek]

Top notch work. Great little rig and a fantastic set of useable tools.
p_t