Chargemaster Reducing Inserts Featured

Chargemaster Reducing Inserts

In Blog by Rich13 Comments

Today I’d like to give you guys some information on some chargemaster reducing inserts made by David Moore. If you’ve not heard of these, it’s a much more elegant approach to the straw mod method of tuning your RCBS Chargemaster Combo dispenser. The problem with the Chargemaster Combo out of the box tends to be that it starts to dispense a charge, and does so at a rate that exceeds the scale’s ability to keep up. So as the Chargemaster approaches the desired powder charge, the scale sends a signal saying “SLOW DOWN” or “STOP” but by the time the dispenser slows down or stops, it’s already overthrown the charge. Now you have too much powder in the pan, and you have to dump it and start all over. There are ways to address this! Read on!

Chargemaster Reducing Inserts

This is what the reducing inserts from David Moore look like. It’s either a brass or aluminum insert, that’s made to order on a manual lathe. Most of the dispenser tubes on the Chargemaster combos measure around 0.310″ for the inner diameter of the tube. However, there are variations from time to time. That’s why Dave recommends you measure your tube with a set of calipers. Just set the calipers to 0.310″ for starters, lock them, and see if the jaws fit inside the tube. If they don’t, try 0.312″ or 0.314″, etc. until you find the measurement that works. Then all you need to do is talk to the man himself, give him your preference for brass or aluminum, and the measurement and he will make an insert for you! It’s that easy!

Chargemaster Reducing Inserts Brass

Closeup up of one of my Chargemaster Reducing Inserts from David Moore! The insert is brass, and there is a sleeve that further reduces the opening for even more accuracy!

Dave told me he’s sold more than a thousand of these little guys all with positive results. You might notice a small sleeve protruding from the brass insert. He came up with that last fall. I’m calling it the “accuracy sleeve” because it takes the same concept a step farther. By reducing the overall diameter of the Chargemaster tube you prevent powder from clumping and dumping out in larger quantities. This sleeve further reduces the diameter down to enhance the accuracy even further. I’m sure somebody is thinking, “Why not just make the sleeve smaller?” You can, but then you’ve pigeon holed yourself and committed to a single dispensing speed. The accuracy sleeves are press fit into the brass Chargemaster reducing insert so you can tap it out if you are doing some high volume loading and need to get more done, faster! These run $17.99 USD shipped, and that’s including the accuracy sleeve, which you can order without if you don’t want the option.

How Do They Work?

We wrote an article on Chargemaster Modifications a while back and it continues to be a sought after piece of writing on the site. However, there are always new ideas and techniques to enhance the accuracy and speed of the Chargemaster scale. The straw mod we describe in that article, while effective, can be a bit of a pain in the ass to get set up. I’d recently purchased a second Chargemaster scale to double my powder dispensing speed and sat down to do the straw mod on the new scale. It didn’t work very well. Basically, I botched the straw job, and I goofed the saw tooth design and the hole by the hopper more than once. That was where some of the inspiration for trying these inserts came from. To be clear, I could have made the straw mod work with more time and effort, but with the Chargemaster reducing inserts they work right out of the package!

This is how the new scale runs now! I was having trouble getting the straw mod dialed in, but all I had to do was drop this insert in and tweak one speed setting and now it’s running great! The new scale runs faster than my older one, no real idea why that is because I even tried it with identical settings. In any event I just had to bump the third speed setting so it slowed to trickle a hair sooner. In conjunction with David Moore’s Chargemaster reducing insert, this thing is running great now! Now I can set down, calibrate both scales, and get them both running and dispensing charges side by side. This translates into more time on the range, and less time burned at the reloading bench! That’s what these devices, and modifications to them, are all about! Spend your time out in the sun with the smell of gunpowder and the sounds of ringing steel, don’t blow the afternoon in the reloading room!

Wrapping Up

Where can you get your own? Measure your Chargemaster inner tube diameter and contact David Moore. You can email him at: [email protected]You can purchase the Chargemaster reducing inserts on ebay by clicking here! You can also Private Message MDM12 over on Sniper’s Hide. I have to say this is money well spent. These inserts work right out of the box. I put mine into my second Chargemaster that was giving me fits with the straw mod, and proceeded to run more than 30 or so charges just testing speed and accuracy on the first day. I think I had one overthrow and after I tweaked one of the speed settings it has yet to happen again. So keep that in mind, you have to watch your Chargemaster work and you might have to adjust your settings slightly for optimal performance. Once you get it dialed in, though, it throws charges without overthrowing and that’s the biggest thing! It’s great if you can dispense in 15 seconds but if it overthrows 30-60% of the time, how much time do you loose by dumping the charge and doing it again?

Owner and Proprietor of AccuracyTech, LLC. Rich is a Firearms Enthusiast, Precision Rifle Competitor, and Writer. He is committed to bringing readers quality reviews and articles related to the Precision Shooting Sports. If you have any questions for him, please use the contact form on the site.


  1. Hi Rich. Any idea if this is something I can/should do with my Hornady dispenser.

  2. Yea, my hornady is the bane of my existence. I can’t wait to get rid of it when my Prometheus shows up. Yea, the Hornady is that bad… drove me to a Prometheus! I would love a fix until it comes. It would also probably bump up its resale value.

  3. I’ve made them for Hornady and Lyman units. Just need a measurement on the ID of the tube.

  4. Rich,
    Are you running the same settings that you had before now that you are using the insert instead of the straw?

    1. Author

      I am on the original chargemaster, Brandon. The new one runs faster so I had to slow it down.

  5. Pro Tip: Don’t attach the nozzle using shrink wrap. You can’t remove it to clean the powder out after you finish (getting all the powder out with the nozzle on is a PITA) Instead, wrap the stem in a few of wraps of teflon thread tape and screw it in. The threads inside the CMs drop tube will cut threads in the tape. It can then be threaded in and out to clean. I did this to mine and the tape has held up for at least several dozen off/on cycles. When it wears out, just wrap it again.

    1. Author

      Hadn’t heard the shrink wrap idea before. I just used a little electrical tape to hold everything in place. Easy to remove.

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