Pros: Relatively inexpensive; So simple it works
Cons: Might not work with some, modern electronic scales due to a 'lack of reach'
In the field of ammunition reloading, a powder trickler is one of those gloriously simple, comparatively inexpensive, and remarkably useful tools that not only leaves you wondering why you didn't get one sooner; but, after a time, makes you ponder how you ever got along without it in the first place. If you're just chunking out loads that will go 'bang,' you probably don't need one. On the other hand, if you desire consistency in your loads and/or tend to take the time to work up specific loads for each bullet weight for a specific firearm, then you'll find a powder trickler is an indispensible tool. In fact, the function of this tool is so fundamental to the process of 'throwing' powder charges, that most automatic/digital powder measures incorporate the basic mechanism as an intrinsic part of the design.
When measuring charges of powder, whether doing each individually or using a powder measure to 'throw' the bulk of the charge, you will generally weigh each charge with a scale. Once you set the scale's poise to the charge weight you desire, drop your initial charge of powder from either a measure or powder scoop (see Lee's Improved Powder Measure Kit: What D'Ya Want For 10 Bucks?) into the pan, lift the pan with the scoop (an extended tab grasped with the thumb and forefinger), place the pan on the pan support assembly, you will then proceed to adjust the powder charge until the scale's beam pointer is centered on the "0" of the dial plate. Typically, you will want to start with a powder charge just under the desired grain weight and use a powder trickler to increase the charge a kernal of powder at a time to zero.
RCBS Powder Trickler
Most of the major manufacturers of reloading tools have some form of powder trickler. While the appearance will differ from company to company and prices will range from about $10 to $20, the core mechanism is the same for each and they all perform the same function. The version produced by RCBS falls right in the middle of the price range and, for me, has the best combination of ergonomics, aesthetics, and utility. Oh yeah... It also works for the purpose intended.
The basic unit is, essentially, a fairly solid, 5 1/2 ounce, cast aluminum hourglass with two, hollow cones. Separated by a solid center, the top portion is an inverted cone which holds a small amount of powder. Running horizontally through the bottom of this inverted, powder holding cone is a metal auger. A small, circular opening in the 4" long tube allows powder to drop inside where threads pull powder kernals toward the opening on one end as you gently twirl the plastic handle at the other. (A plastic collar on the side opposite the handle keeps the tube from being inadvertently removed from the trickler body. You can pull this collar off to remove the tube, but I've never found a reason to and wouldn't advise doing so as I am suspicious that the plastic collar may prove far easier to remove than to reinstall.)
The whole trickler stands 3 1/2" tall. The 'base' portion has a 2" diameter footprint and while I've never found the need for one, given the hollow design, an extra weight (a section of lead bar or similar) can be inserted to help increase stability or 'anchor' the trickler in place. (Simply put, I cannot remember ever tipping this thing over. And, if you're gonna hit it with sufficient force to do so, I'd humbly point out that you're not pay enough attention!!!) The auger exits from the narrowest portion at 2" above the bottom and extends not quite 1 3/4" from the body. According to RCBS, this places it at "a perfect height for most powder scales." Well - I do find it to be the optimal height for my RCBS 5-0-5 Scale... (see In The Balance, It's Probably All The Scale Most Will Need)
Its simplicity of use is hinted at in the brevity of the 'instruction manual:'
"To use, fill the large capacity powder reservoir with powder. Several turns of the knob will be required to start the powder feeding through the tube. The, twist the knob until the desired amount of powder trickles into the scale pan. The powder will be dispensed faster by turning the knob in a clockwise direction."
How much powder? How much do you need? Let's just say that a couple/three tablespoonfuls have been more than enough to get me going with most extruded powders. Remember, you're looking to trickle a kernal or two of powder at a time; thus, it really isn't necessary to "fill" the reservoir.
In my experience, the RCBS Powder Trickler works best with extruded powders. It does work with ball powders, but there is a tendency for the auger to move, or 'trickle,' too much at a time; particularly when you're down to measuring out that last kernal or two. Even with extruded powders, you can't just twist the knob as if you were spinning a top. If you're careful, you can get it to where it drops, literally, a single kernal of extruded powder at a time. This does not mean that the powder trickler is slow to use. It just means that you have to pay attention. And, as I have noted repeatedly, when it comes to reloading ammunition, if speed is your primary criterion, good luck to ya'. In fact, the school of reloading (and shooting) I came up in preached that if you didn't take the time to do it right, you might not get the opportunity to do it again.
If there is one 'flaw,' and I don't see a way to get around this with any of the designs, it is that there will always come a point where the powder drops to a point where the auger cannot pick up any up through the hole, despite there being a certain amount in the bottom. While you simply add more to the reservoir at that point, it is something to bear in mind when it comes time to empty the trickler. I find the best way is to put a finger over the opening in the auger tube while you pour the powder from the reservoir.
Remember what the instructions said about it being faster to turn the knob in a clockwise direction? Some powder will always work its way into the knob end of the tube. Powder kernals will also be 'trapped' in the auger screws. Therefore, once you've emptied the main reservoir, you must hold the open end of the tube over your powder container, remove your finger, and tilt/empty the tube itself.
At an MSRP of $16.95 (mine still has an $8.59 price tag on the box from over two decades ago), the RCBS Powder Trickler is not the "cheapest" design on the market; but, it's also not the most expensive. When the company states that it is the "perfect height for most powder scales," they primarily refer to "mechanical," balance beam scales. Many of the more modern, electronic powder scales have a wide enough platform, or base, that the 1 3/4" extension of the auger tube may not be sufficient to reach the pan.
When it comes to weighing charges, it is far easier to "add to" than "subtract from" the pan when weighing. That is the precise purpose of a powder trickler - to add that last little bit. Remember - 'Tis better to give than receive... Or ... For those who remember Brylcreem - "A little dab'll do ya."