Moly Bullet-Coating System
Using Thumler's Tumbler and Plastic Jars
By Larry Medler, Anyrange@comcast.net
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Moly-coating of bullets is controversial. Many folks believe moly reduces fouling, and prolongs barrel life. Others argue it really doesn't help much, if you start with a good barrel. I'll just say I prefer to shoot moly bullets in many of my guns. Using moly lets me fire more rounds between cleanings without losing accuracy. I also think barrel life can be extended by using moly-coated bullets. Apparently Norma agrees. Norma Moly Tests.
Heart of the System -- Thumler's Rotary Tumbler
I already had a Thumler's Tumbler so it seemed logical to use it for this project. Two 40-ounce Peanut Butter (PB) Jars fit perfectly inside the unit. The plastic jars in the Thumler's Tumbler are my answer to controlling moly mess. One jar is for cleaning the bullets (left jar) and the second jar is for the moly coating process (right jar). The extra jar in the center is to show the Jar's perfect fit in the tumbler drum.
My NECO Moly Kit (sold by Neconos.com) came with three bottles of steel shot. For this project, I used one entire bottle of shot in a cleaned, clear plastic 40-ounce PB jar. I placed the jar in the Thumler's Tumbler and watched the steel shot in action. The steel shot appeared to have a nice rolling and sliding action as the jar turned end over end in the tumbler.
Sources for Thumler's Tumblers:
Clean and Polish Bullets
The first step in the moly coating process is to clean the bullets. I use a 40-ounce PB jar for the cleaning stage also. The small packet of ground corncob media in the NECO kit was just right for the 40-ounce jar. The tumbler can hold two jars in its drum. So, while one batch of bullets is being moly-coated the next batch can be cleaned.
I add a small amount of MidwayUSA Brass Polish to the corncob. This really makes the bullets shine. I use a simple sand-box toy to separate the bullets from the corncob media.
Separating Shot and Moly-coating the Bullets
To make this a truly first class operation, just add the NECO Sieve. It works fast and reliably. I have also placed the nozzle of my shop vacuum over the work area to act as an exhaust hood. Some moly dust will float up as you dump the jar of steel shot and bullets into the sieve. The Shop Vac. takes it away before it settles on the bench or floats to your face.
NOTE: Moly Dust is not a good thing for your lungs. It's not a bad idea to use a paper mask.
My current process is to tumble for three (3) hours using between 5 to 6.5 grains of moly per batch of bullets. In a batch, I run either fifty 30-caliber bullets, or one hundred 22-caliber bullets.
So far I have coated over 8500 bullets in 134 batches. The Moly PB Jar has been tumbled 400+ hours with the steel shot. It still looks and feels as good as new.
Pouring the Steel Shot Back into the Jar
The two-part NECO sieve has a shot catch-pan below the sieve body. I made a notched wooden lid to fit the catch pan for pouring the shot-balls back into the PB Jar. This works great with minimal dust. Again notice the shop vac nozzle is used to catch any moly dust generated while pouring the shot back into the PB jar.
NECO Sieve Set
8" diam. with .187" screen holes, $71.95 from Neconos.com. The catch pan, sieve body & cover are brass. The strainer screen is stainless steel.
Finished Product -- Moly-Coated Bullets
The last step in my moly process is to place the moly-coated bullets on a terry cloth towel for a quick wipe. The wiped bullets are as clean to touch as the sample bullet that came with the moly kit. I do not use the wax step. Overall, by using the PB jars inside the Thumler's Tumbler, this is not a messy process. And the Thumler's Tumbler is very quiet with the lid on--the rubber drum liner dampens noise very well. For convenience, get a 24-hour programmable appliance timer. Look for a timer that can turn the Tumbler off after a pre-set period. But make sure it won't turn the machine back on again the next day!
So this story is for those on the moly edge, if you have a Thumler's Tumbler go for it.
Text and Photos Copyright © 2004, Larry Medler, All Rights Reserved. Other materials Copyright © 2004, 6mmBR.com, All Rights Reserved, no reproduction without advanced permission in writing.