Drop Tube Metering, or This Dog Too Lazy to Scratch His Fleas

[tangsight]

I load my Pedersoli model 74 Sharps 45-70 volumetrically. When I pour the charge into the drop tube, it's a manual operation. I hold the case at the bottom of the tube while I pour the charge into the funnel end from a small, spouted brass dish (the kind you get with a scale, yes, I have one). It seems to help to sing "I'm a little teapot, short and stout" while I do this.

Now this part everyone needs to read carefully: I hate having to be part of the apparatus. Why do I have to be careful to pour the powder slowly? Isn't there a metering device I could buy somewhere that would slow pour the powder for me? Or a drop tube that mechanically retards the flow of the powder into the case in some way? Or maybe I just don't understand the concept of a drop tube.

I know! I'll buy an old windmill......

[trails4u]

If you gotta ask......you're just not that into it.

Welcome to the blissfully painful world of BPCR!

[Nueces]

I would think an easy thing to try would be a glass or metal funnel with a small, long neck. Idea is it would act like an hour glass timer. Glass would make it easy to check for powder bridging. Avoid plastic because static would encourage bridging.

[tangsight]

Yeah, I'm too old to play with all the toys I have, and unwilling to commit to just one.

The problem seems to be the powder column height is never the same. I can't help but think I am the variable, and something mechanical instead would create greater consistency. Also I believe someone here must have already thought of a really cool Rube Goldberg type of device that would fix me right up.

[tangsight]

Nueces, you and I been drinking some of the same poisoned water. I have spent most of this evening searching for a glass funnel with a long enough stem!

[Gunlaker]

There are ways to automate it if you like. A couple of friends have made devices where a motor is used to vibrate a small funnel into the drop tube. The funnel has a relatively small hole so the powder slowly drops through as it's being vibrated. You just pour the powder charge into the funnel and wait.

Chris.

[tangsight]

Gunlaker, you said more than you think. Now I know, because you said "a couple of friends" of yours had worked around the manual aspect of the drop tube, that I am not the only one who is tired of "I'm a little teapot", or various other ditties of the correct seven second duration. I gather the motorized funnel into which the charge is first poured is not the funnel at the top of the drop tube, but a second funnel above that funnel? The motorized device is completely separate, right?

[Gunlaker]

Yes that's basically it. From what I remember, the second funnel is on a piece of thin spring steel. A small electric motor makes it vibrate. I think the electric motor has some weight added to one side of the output shaft to make it wobble.

Chris.

[Don McDowell]

The problem seems to be the powder column height is never the same.

That's what compression dies do for you. Smash the powder to the same level every time. Of course a lot of your difference in column height could be from the "volume measure".

[Nueces]

Nueces, you and I been drinking some of the same poisoned water. I have spent most of this evening searching for a glass funnel with a long enough stem!

TS, you could use a not so long stem funnel just to feed your drop tube. The funnel just slows down the powder rate.

I think a good place to search for such glassware would be a lab supply outfit.

[tangsight]

Don: If I understand your reply, you are referring to my original statement that I charge my cases volumetrically, rather than weigh them. Well, I do weigh maybe 1 in 10; they seem to average about 68.5 grains (FFg Goex, screened to remove the fines with a Cal Graf Master screen. Goex seems to prefer significant compression). The whole point of my charging by volume is to obtain uniform column height. When I don't, I make the assumption that it is because of the presence of the human element. Compressing columns of different heights to uniform depths is tantamount to creating a different amount of compression for each cartridge, it seems to me. Of course, I don't understand the drop tube concept, so by inference you could make the argument that I don't understand the concept of compression, either. By the way, if I were to use a glass funnel with an integral 6" stem that has an inner diameter of 3/16" as a drop tube, would I see significant retardation of the powder flow, an "hour glass" effect such as Nueces refers to above?

[JCherry]

I use a Belding and Mull powder measure, dump the powder in the case, then with an electric pencil as a vibrator I vibrate the powder down just a bit in the case then use a compression die.

Have fun,

JCherry

[Bent Ramrod]

Could you just put a drop tube on your powder measure and turn the crank down slowly to open? Once the measuring drum is full, using consistent technique, the rate at which it is opened and emptied at the bottom should not affect the powder column. It would, though, allow a slower trickle into the case than opening it all the way at once.

I've toyed with doing this on my Ideal #5 measure, which is set up for either a short spout or a long drop tube as the operator wishes. However, I still check my technique by dumping into a scale pan, weighing and pouring slowly as you do. If I could get fifty charges in succession within + or - a half grain, I would go to the slow crank technique, but weighing every one always shows an outlier or two.

I'm probably overly finicky about this, as a friend checked a ladder of powder charges one time and did not see a significant change in vertical at 600 yd until he was three grains away from standard. This with a .45-70. But I have to be "in control" of everything, so I do the extra work.

[JSnover]

I use a Belding and Mull powder measure, dump the powder in the case, then with an electric pencil as a vibrator I vibrate the powder down just a bit in the case then use a compression die.

Have fun,

JCherry

Right there! Vibrate the case, not the funnel or the tube, unless your powder is bridging in the funnel.

[Nueces]

You could try this idea out right now by folding a piece of hard finish paper or card into a cone, making the outlet the size you want. Hold it over your drop tube and pour your powder charge into it, see if the idea works for you.

[Don McDowell]

Don: If I understand your reply, you are referring to my original statement that I charge my cases volumetrically, rather than weigh them. Well, I do weigh maybe 1 in 10; they seem to average about 68.5 grains (FFg Goex, screened to remove the fines with a Cal Graf Master screen. Goex seems to prefer significant compression). The whole point of my charging by volume is to obtain uniform column height. When I don't, I make the assumption that it is because of the presence of the human element. Compressing columns of different heights to uniform depths is tantamount to creating a different amount of compression for each cartridge, it seems to me. Of course, I don't understand the drop tube concept, so by inference you could make the argument that I don't understand the concept of compression, either. By the way, if I were to use a glass funnel with an integral 6" stem that has an inner diameter of 3/16" as a drop tube, would I see significant retardation of the powder flow, an "hour glass" effect such as Nueces refers to above?

So long as the base of the bullet contacts the powder, the powder level in the case before seating a bullet matters little. Using a compression die will make sure the powder is compressed enough to allow the bullet to seat fully on the wad without deforming the nose. Screening Goex is an excercise in taking up time for little to no benefit on the target.

[country gent]

Ive played with a "double funnel" for awhile on my drop tube. A 2 funnels 3" apart the top one off center to the lower one the lower one having a slightly larger hole that the upper one does also. In theroy the upper funnels small hole "smooths" out the lumps from the slow pour into the lower funnel and being off center the Bounce and swirl created evened it out more. It didnt make any visible diffrence in Accuracy, extreme spread, or standard deviation for me. I made the 2 funnles and used a 3 section from a pop bottle between them. I have seen drop tubes set up with the vibrators from Toys at the adult book store used to cause vibration in the tubes and funnels also. I simply use the slow pour and then compress to depth required. I throw my charges with a Belding and Mull measure also. weigh them and bring to weight. My drop tube is sliding and I set the case under it let it down and pour the charge thru it into the case. Seat a wad and compress to needed depth. With Olde Ensford my loads are normally 15 fps extreme spread or a little less.

[tangsight]

Nueces, I like the idea of the paper cone. That would at least tell me what the approximate effect of a given orifice is on the powder flow rate into the tube. I wonder if I could combine that trick with something to plug the hole until I was ready to let the flow commence (like, say, a sharpened pencil). That way I could dump the charge into the paper cone, pull the pencil, and back away, secure that if it all goes to hell, at least it wasn't because I was inconsistent in some way.
Bent, I am attempting to remove human involvement from the process. Innovative as your idea is to rotate the charged powder measure drum slowly, my hand is still there, so it is not the way I want to go.
JCherry, I may have sent the discussion off in the wrong direction initially. When I described a mechanical device to retard the powder flow, all I meant was something like a mechanical hand that would spill the powder into the drop tube at the same slow rate as I do when I'm singing "I'm a little teapot". Something that would rotate the scale pan 90 degrees in seven seconds.
Don, I hope you are right, because if so, the reasons I am not grouping lie elsewhere, as I always make sure the base of the bullet is in contact with the overpowder wad.

[tangsight]

Country, sorry, had honeydews for a few minutes, back now. Sounds like you tried most of the rabbit holes I am sniffing down and went back to a fundamentals only approach.

[country gent]

WHat might work to distrubute the pour like you want is a metering wheel in a housing with small hoppper on top. In use pour your charge in the hopper turn the wheel slowly letting it run a small amount of powder thru as it turns. Its that or a powder trickler type set-up with a coarse thread in the bigger tube. The issue with these will be making sure all the powder is out of them between charges. A hard wood housing to mount on the drop tube with a 1/12" -2" drum and handle with the funnel above. Drum would need a series of crosscuts or shallow holes cut around it so when turned it carries and drops just a few grains of powder at a time. The trickler type set up would give a smother more even flow into the tube and could be set up as a motor driven unit.