Tips affixed to the dispenser tube on RCBS Chargemaster 1500 to avoid excess dribbles

[Cassidy]

I use the RCBS Chargemaster 1500 and find it's quite efficient in helping me load powder into cases. However, sometimes it dribbles a few granules at the conclusion of a powder load, and I have to repeat the load to get it accurate.

A friend of mine made a tip for me (pic) using his metal lathe, which I have affixed onto the dispensing tube and it seems like it helps resolve this problem to some extent, but I still get excessive dribbles and have to repeat loads maybe once out of every 10 cases. Perhaps there are other tips to affix to the end of the dispenser tube that might work better. What do you think? Please advise me of better alternatives (tips?) to address this problem.

 

[Tokay444]

I use the MK Machining slip on reducer, and tuned Chargemaster to great success.

 

[GLShooter]

I have a set of brass insets for mine that I got off the Benchrest forum a couple of years ago. I see them on E-bay and Amazon that are done up in plastic. IMine have different sized holes as some powdr is so fine overcharging is a given major issue. Michael David Moore was the guy I got mine from.

Greg

 

[Mark W]

I did the McDonalds Straw Mod only I used a Chik Filet straw (because it’s the only fast food that I’ll actually eat) and it works great.

Bench Hacks 101: Modified Straw Trick for ChargeMasters « Daily Bulletin

Here's a clever, easy modification for your RCBS ChargeMaster electronic powder dispenser. Many folks use a McDonald's straw to smooth kernel flow out of the dispensing tube. Forum member Mike S.

bulletin.accurateshooter.com

 

[Homerange]

Perhaps there are other tips to affix to the end of the dispenser tube that might work better. What do you think? Please advise me of better alternatives (tips?) to address this problem.

Reduce the aperture size further.
IIRC the alloy sleeve I turned up was just over 1/4" and at least an inch long and while it does slow the dispense time some, powder clumping near the nozzle is nearly eliminated as are overthrows.
Ensuring the CM is dead level is also important as is having it in a solid base to isolate it from bench vibrations although loading workflow can minimize dispensing issues that might shake clumps from the tube when in trickle mode.

 

[Enosiophobia]

McDonald's straw. Problem solved.

 

[mikecr]

A tip and programming helps but the issue is really that jog speed(trickle) is not adjustable.
And it really needs to be adjusted for different powders.
What I did for this, that I couldn't go without, is put a 10ohm potentiometer inline with the motor. This barely slows any speed except for jogs.
While I'm at jog speed I adjust the pot for single kernel drops and watch the scale. With this, I've gotten good at hitting scale response with better accuracy than fully indicated (as checked with an Acculab scale).

 

[Homerange]

McDonald's straw. Problem solved.

So you might think however here in NZ McD's straws are the wrong size and couldn't find any others that would fit so with a lathe it was pretty simple to make one.

 

[Adam in WI]

@mikecr what is the linear weight bias do?

 

[Nick Caprinolo]

A tip and programming helps but the issue is really that jog speed(trickle) is not adjustable.
And it really needs to be adjusted for different powders.
What I did for this, that I couldn't go without, is put a 10ohm potentiometer inline with the motor. This barely slows any speed except for jogs.
While I'm at jog speed I adjust the pot for single kernel drops and watch the scale. With this, I've gotten good at hitting scale response with better accuracy than fully indicated (as checked with an Acculab sc

Yes what is the linear weight bias and what does it do?

 

[10XSHOOTER]

I cut the neck, shoulder and about 3/8" of the case from a .243 Win. I then wrapped blue painters tape around the tube until the cut piece would go on and stay put! Works for me.

 

[CharlieNC]

Smaller ID exit helps. Looking around I observed a bic pen where the tube size was close to the ID on the CM, and the bic writing tip tapered down quite a bit. After a little sanding it fit well, and trickled more precisely. But it was very slow, so I stayed with the commercial brass insert as a compromise. But I don't recall if the primary dispensing speed can be increased to overcome this?

 

[Bamban]

I turn down 224 barrel drops for the reducer. The end that goes inside the dispenser is chamferred with a center drill. I think the rifling might have helped with the repeatability and reproducibility. I made a few for friends and they love them.

 

[tmwinds]

Try this. Works for me. You can also reprogram the speeds to dispense to your liking.

 

[MislMan]

My overcharges are typically 0.1-0.2. I use tweezers and pick a couple of grains out to get down to preferred weight.

 

[dcali]

These mods aren’t all they’re cracked up to be. If you test them, you’ll find that they may or may not reduce overcharges, and there’s a good chance that it will slow down the whole process. The results depend on the powder you’re measuring. After fiddling with them for a while, I decided that running it stock and tweaking the software parameters gave the best performance. Mileage may vary.

 

[Doom]

The primary tweet is tuning the software to the powder. The shift points, especially to slow and trickle need to be soon enough that the level of powder in the tube is not too high. That and the 243 case neck. I can run IMR 4064, IMR 8208, and VV N135 loads in 20 to 30 seconds with almost no overcharging.

 

[Straightshooter1]

The primary tweet is tuning the software to the powder. The shift points, especially to slow and trickle need to be soon enough that the level of powder in the tube is not too high. That and the 243 case neck. I can run IMR 4064, IMR 8208, and VV N135 loads in 20 to 30 seconds with almost no overcharging.

What I've highlighted is what I find is what's important to keep the trickling from dropping overcharges, which some of the tuning of the until helps with. So, not only tuning the timing of the CM speeds, I found using a long piece of straw that goes all the way back in the tube allows me to adjust the rate at which the powder enters the tube. With the tuning the CM electronics along with the straw adjustment for the size of powder I'm loading, I get pretty consistent powder throws in less than 30 sec and sometimes under 20 seconds. And because I'm using a clear straw that sticks out of the front where I can see what powder is laying inside, if the charge might be a little light, I just lightly tap the tube with my finger to drop a kernel or two or whatever is needed to get to the indicated target weight.

Where what that straw adjustment looks like in my CM:

 

[mikecr]

Very good Straightshooter1. I did the same. Like you said, it prevents occasional clumping mass heading to the pan.

What I referred to as a "linear weight bias" is a light aluminum weight that puts my relatively small charges (~50gr) into the middle of mechanical scale movement.
With scales there is magnetic and mechanical hysteresis.
In my experience with instrumentation and controls, calibration accuracy is often not linear throughout the entire range of spring biased/mechanically damped mechanisms. Accuracy typically takes a hit nearest extremes of scale.
Like with a torque wrench, or pressure gauge etc., it's best not to rely on measures near the very bottom or very top of range.

 

[Adam in WI]

So, in effect you're basically pre loading the scale. If I understand this correctly, the scale is least accurate off-zero to a certain weight. Adding the aluminum weight overcomes this initial inaccuracy by applying a small amount of preload. For arguments sake; doesn't the pan accomplish the same thing? The pan weighs 152 grains, and the CM's listed maximum is 300 grains. That would put you right in the middle since you're not actually at "zero" with the pan in place. The zero displayed with an empty pan is rather your tare with a 152 grain load already in place.