Black Powder loads and accuracy

[BCRider]

I may have missed it in the replies but a warning to watch out when using lighter loads that you use a filler over top of the powder so there's no air gaps.

I know that in my cowboy action .44's 30 grains of powder is the minimum I can use and still have enough motion in the lever to seat the ball against the powder. Any less and I'd need a second powder flask to dispense some cream of wheat or oat bran as a filler. Needless to say the ball is seated rather deeply with this setup. As it happens though I like the way the 30 gns feels from both my pair of Uberti Remingtons and the mixed ASM and Uberti 1860 setups.

Because I need to get the guns loaded and get back to helping out in the match I just load powder, ball and a drop of Canola cooking oil over the ball for lubrication and to seal off any slight gap between ball and chamber.

As it happens one of my 1860's shoots this mix of powder and deeply set ball VERY accurately. As good as I can do with any of my other cartridge guns. Some of which are rather good for bullseye shooting.... which is to say that it's me that is the limit. We're talking about 1.5 inch group at 15 yards to set the standard.

 

[Branko_D]

You're right about the filler to prevent air gaps. In particular the NMA has limited travel of the loading lever. However, are you sure your measure is well calibrated? 30 grains of BP (by volume, using 1ml = 15.43 grains as conversion rate) seats not so deeply in my Uberti NMA. 33 grains and a .457 ball (I could use .451) is flush with the cylinder face.

I could set down the ball just fine with the relatively limited lever of the NMA and 25 grains of BP and a .457 ball with a tad of grease under the ball, pretty sure it would compress with even a bit less.

 

[BCRider]

Branko, I use a flask with the measuring spout. I've tested the spout for the drop weight and it was initially dropping 28gns of 3f. I used my Dremel to lightly hog out a little of the inner wall and it's dropping an honest 30 gns now. And with that much powder and with the ball seated directly onto the powder the nose of the balls are roughly 3/16 to 1/4 inch below the face of the cylinder. And that's just about as far as the ram goes. Are you using a felt wad by any chance?

The chambers in my own Uberti NMA's is a constant diameter from mouth to back wall. I also have an older Uberti Colt 1860 that has a reduced diameter for the powder and the balls on that gun sit much closer to the front face with the same 30 gns. I wonder if we're looking at our NMA guns being from different vintages of production with a change in one direction or the other between our guns?

 

[Branko_D]

Oh, I think I understand the source of confusion. We use different volumetric grains, since it is a wonderfully undefined unit. I made my own set of measures based on the assumption that density of BP is same as water, so 1 cc = 15.43 grains (volumetric). Measuring the cylinder, every chamber has a volume of about 3.23 cc (it seems straight walled, but... well, I can't measure that readily, so it could be a bit less).

2.4cc and a .454 ball (37 grains volume by my reckoning, half of it filler and half of it BP) is about flush with the cylinder face. 2.14cc (33 grains volume by my reckoning) with a bit of grease under the ball and a .457 ball is almost flush with the cylinder face. 1.94 cc (30 grains by my reckoning) and a 180 gr SWC with a thin layer of grease below it is flush with the cylinder face when well compressed, and is about the strongest load I use (makes for a nice kick, a lot of smoke, and a nice bang - would be a nice hunting load).

If you measure actual weight of BP to calibrate your volumetric scale, it depends if it has settled and differs from batch to batch, and it's not exactly the same density as water (well, it's pretty close, but varies by manufacturer), so you can get something slightly different as your volumetric grain.

Volumetric grains :banghead:

 

[BCRider]

There ya go. That would explain it.

And we should likely both duck and run before the mob gathers the pitchforks and torches to mull over the issue once again....

I'm pretty well set up with a local supplier of Goex so that's primarily what I use. And with the size of bores I shoot in black I'm also settled in on 3F. And I figure that with all the tipping and pouring it is going to be fairly consistently shaken up. But you're right on the settling as well. When I shoot the long guns I use a small dedicated measure filled from a horn instead of the flask with spout. My "drill" is to fill then tap the edge twice to settle the measure and then fill to a little crowning heap that just starts to overflow. That method drops a pretty consistent 62 to 63 gns of powder weight for my flint and cap lock 50cal rifles.