RCBS Powder measure

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chrt396

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I have an RCBS powder measure that is either defective..or I'm horribly dense.
I was loading either 9mm or 40 cal loads the other day and decided to use Blue Dot powder. I had it..so why not use it. Is it me...my machine..or what? Every time on the down stroke of the charging handle, the thing would bind and stick. The same thing happened last night using AA#2. Not a nice smooth up and down, but a binding feeling. I know this is common with some powders, but I'm starting to feel as if it is my measure.
Plus..I could be loading for 5.6g. and I run 5 or 6 test charges to reassure proper weight, and after I conclude that the measure is throwing 5.6g...15 rounds later, it's throwing 5.8g. No consistancy! What is going on? Is there a better powder measure out there where this crap doesn't happen? Is there one that is KNOWN for it's accuracy? I'm growing tired of this powder measure. It's fairly new and I've cleaned it and wiped it out..and still..it binds!
 
RCBS makes a great measure. Could yours be bad? Yes, but unlikely.

Take it apart, clean it thoroughly, and lube it with Tuf-Glide. It should run smoothly. Always let it dry thoroughly before using. Eventually you won't need lube at all.

If that doesn't do it, call RCBS.
 
I agree with Walkalong. My Uniflow is great.

I have had to lube my Hornady L-N-L measure a little to smooth out its operation. Without the lubricant, it sticks badly in operation of the progressive press. Make sure the dry lube's carrier has flashed off before using the measure. Otherwise, it will cause a mess.

Don't clean the measure between uses, just wipe it out. Some of the coatings, such as graphite, on powders have lubricant properties. Cleaning the measure with some solvent or other cleaner removes this material.

After a while, the inside of the measure will have a coating on the metal that will make the separate step unnecessary.

I find consistency of operation is key to consistent charges. Do it the same way every time. I like to operate it easy with as little vibration as possible. Some like to wrap the measure with the drum stop on each stroke. Key is do it the same ever stroke.

Also, it takes lots of "test" charges to get the powder column to settle. I throw 15 or so before I start weighing the charges. I don't start loading until I get three charges in a row that are the same. When adjusting the drum cavity, it may take 5 or 6 charges to get the weights to settle down again.

Some variation in the charge weight is normal. The larger the charge, the larger the variation. With pistol charges, a 0.1 grain or so variation is ok.

I find the measure is better with a powder baffle. make sure the holes in the baffle are cross ways to the operation of the drum. Others have success without the baffle.

Flake powders will sometimes have a bit of reisitance in operation as the drum cavity cuts a few flakes during operation. It is not as pronounced as with stick powders but it can be felt. Normal, but adds to the difficulty of consistent operation.
 
Two things that helped my RCBS measure

1) Absolutely go for a powder baffle, they're about 6 bucks and help out a lot. Like a lot of others I don't know why they don't just ship standard. You could probably make your own in a few minutes with some tin snips too if you were so inclined.

2) Are you using the "Large" size powder cylinder or the "Pistol" size. Again they usually ship with the large but i found that when I get to really small pistol size throws, the top of the metering step is so close to the edge of the cylinder it can start to bind up. The "Pistol" size is advertized to throw 0-50 grain charges so short of some 30-06 loads it does a good job with finer increments even for rifle cartridges like .223 and .308.

Those two improvements will really help out a lot, I'm sure others might chime in with a few more suggestions as well.
 
Another vote for the baffle

Also, do you have the handle placed so you bring it up and then down , or the other way around? I get more consistent drops with the handle in the down position to start, flipping it up hard, then bringing it down - it seems too settle the powder better. Another thing - keep your measure between half and three quarters full - you'll get more consistent drops as well
 
Like mentioned above, take that bad boy apart. I was plagued with inconsistent throws and after taking it apart I found casting slag inside the assembly.

I also second the powder baffle....I made my own with tin snips and a aluminum can. If your google foo is great I'm sure you can find the instructions/templates.
 
Baffle actually made my Uniflow less consistent with Trail Boss, so I took it back out. I haven't tried it yet with other powders to see how it works. That's how much Trail Boss I shoot. :) I say, check before, then after baffle to see if it helps, don't assume it automatically will help.
 
Mine does that sometimes, I don't know if a baffle would help, probably wouldn't hurt, but I definitely know what you are talking about. What I can say is that is is worse on powders like Blue Dot and 800-X. Flake powders that are mostly shotgun powders. Anyway, when you use these powders, make certain you weigh EACH CHARGE! Those two powders in particular are known for measuring very poorly. They can make magnum loads, but they can blow up guns if not careful. If you look at data for these powders over the years, they consistently reduce the maximum charge, probably due to folks not weighing them and using them to load "hot" loads, in say, 10mm.

Anyway, I use the exact same setup, I use the meter, but I set it off a little so that I have to use the trickler next to the pan on the scale to finish the charge (the RCBS one is great, heavy and won't tip and will reach the pan). That way I get safe 800-X and Blue Dot loads.

How I learned my lesson was years back I loaded a bunch of low power 9mm and I used the meter and I checked about every 10th load. But somehow several loads went by that were low enough to cause the bullet to stick most way down the barrel. Pulling them shows that most were fine, but there were some that slipped through.
 
Great measure. One of the best. Do this....

• Baffle. Make your own using the free instruction. Do a Google on "Uncle Nick’s Powder Baffle Templates".
• Lube with powdered graphite from WalMart or Home Depot. It's in the key and lock section.
• Make sure you have the small pistol/barrel option for small loads, and not the large diameter rifle. The small one is about 1/2" dia and the large one is about 3/4" dia.
• Put a wave washer or o-ring on the adjuster shaft between the hex and the knurled adjuster nut. This will keep the lock nut from moving. Newer models already have this.
• Double bump the stop at the top of the stroke and then again at the bottom of the stroke. So when you operate it, it sounds like lift knock-knock, lower knock-knock. That will help give you a more consistent density.
• Always put the first 10 dumps back into the measure. The density hasn't settled down enough to be consistent.
• Never set the measure by using a single "dump". If you want 5.6gr, then dump 10 "dumps" and dial-in the measure at 56.0gr.

Have fun !
 
fractal7 said:
Two things that helped my RCBS measure

1) Absolutely go for a powder baffle, they're about 6 bucks and help out a lot. Like a lot of others I don't know why they don't just ship standard. You could probably make your own in a few minutes with some tin snips too if you were so inclined.

2) Are you using the "Large" size powder cylinder or the "Pistol" size. Again they usually ship with the large but i found that when I get to really small pistol size throws, the top of the metering step is so close to the edge of the cylinder it can start to bind up. The "Pistol" size is advertized to throw 0-50 grain charges so short of some 30-06 loads it does a good job with finer increments even for rifle cartridges like .223 and .308.

Those two improvements will really help out a lot, I'm sure others might chime in with a few more suggestions as well.
Click to expand...
There is a large or a small size powder cylinder??? What is that? HHMMM..maybe that's the problem! I load my rifle with the RCBS Combo master so I only use the powder measure for pistol. I have the baffle. Someone mentions to put the holes in the baffle crossways with the cylinder?
 
rfwobbly said:
Great measure. One of the best. Do this....

• Baffle. Make your own using the free instruction. Do a Google on "Uncle Nick’s Powder Baffle Templates".
• Lube with powdered graphite from WalMart or Home Depot. It's in the key and lock section.
• Make sure you have the small pistol/barrel option for small loads, and not the large diameter rifle. The small one is about 1/2" dia and the large one is about 3/4" dia.
• Put a wave washer or o-ring on the adjuster shaft between the hex and the knurled adjuster nut. This will keep the lock nut from moving. Newer models already have this.
• Double bump the stop at the top of the stroke and then again at the bottom of the stroke. So when you operate it, it sounds like lift knock-knock, lower knock-knock. That will help give you a more consistent density.
• Always put the first 10 dumps back into the measure. The density hasn't settled down enough to be consistent.
• Never set the measure by using a single "dump". If you want 5.6gr, then dump 10 "dumps" and dial-in the measure at 56.0gr.

Have fun !
Click to expand...
What in the measure do you lube with the graphite. The whole interior workings of the measure?? Hopper and all?
 
My technique is to go up smoothly to top, then go down and at bottom..go "Tap..tap!" I keep the technique identical throughout the charging process. When I am adjusting the measure, I test weigh about 5 or 6 charges once I get the weight I desire. Therefore..if I want 5.2 grains...I adjust until I hit that measurement and then repeat the test 5 or 6 times more to check for consistency. The problem is..there can be a great degree of variation in some powders and the binding problem drives me NUTZ!!

As I said before...I don't know what cylinder I have in the measure...small or large..but could that be the problem???
 
What in the measure do you lube with the graphite. The whole interior workings of the measure?? Hopper and all?
Click to expand...

I take out the drum the handle attaches to and lube it with graphite. I also lube the inner part of the casting it rides in. Whenever mine is feeling sticky this always makes it smooth as butter.
 
chrt396 said:
There is a large or a small size powder cylinder??? What is that? HHMMM..maybe that's the problem! I load my rifle with the RCBS Combo master so I only use the powder measure for pistol. I have the baffle. Someone mentions to put the holes in the baffle crossways with the cylinder?
Click to expand...

There are two metering drums available for the Uniflow. A large and small cavity. The small cavity is appropriate for small charges.

If the holes in the powder baffle are placed directly over the opening in the cavity, it does not baffle.

The line between the two holes in the baffle should be parallel with the rotational axis of the drum. That way, neither hole is directly over the drum cavity opening.

Put another way, orient the measure so that the metering drum adjuster is pointing directly at you. Install the baffle so that the holes are crossways to you, one hole left and the other hole right.

I have found variable charge weights thrown if the powder baffle has not been installed this way.
 
My Uniflo, bought decades ago, came with both cylinders, I use the small one for everything, even 30-06. And the powder baffle is wonderful.
 
If you have a turret press, the baffle is useless, otherwise it works really well.
Click to expand...

Since the baffle is there to combat the weight of the column of powder within the hopper, and is therefore independent of press style or make, that statement makes no sense.

What in the measure do you lube with the graphite. The whole interior workings of the measure?? Hopper and all?
Click to expand...

The rotating drum is the part that gets lubed. You can simply remove the fill cap and squirt some dry graphite down in there once a week. If you were to reload more often, the graphite would rub off the gun powder and lube the press for you. The gray stuff on gun powder IS graphite.

As I said before...I don't know what cylinder I have in the measure...small or large..but could that be the problem???
Click to expand...

Yes, by all means. It's a 2 minute job to loosen the 3/4" hex nut on the front of the measure and withdraw the piston through the hopper, then measure the piston diameter. The "pistol" size measuring drum uses a piston about 1/2" in diameter.

BTW, if you want to do a jam-up lube job, once the piston is removed the drum is free to slide out either side.

PowderHopper_Parts.png
 
On a turret press, if you have the powder measure mounted in one of the turret holes, the action of rotating the turret bounces the powder down under the baffle rather than letting it gently flow over. After a few rotations the powder is packed up enough under the baffle that the baffle no longer serves any purpose. Because of that your first few powder charges when the baffle is still not packed up will be much different than the charges after it's packed up. This wouldn't happen on a progressive press where the powder measure isn't moving around, or on a single stage where the powder measure isnt in contact with the press. So yes, in my experience the type of press does matter.
 
Walkalong said:
The baffle will still help.
Click to expand...

Well then use if it makes you happy, I was just sharing my personal experience that showed that using the baffle on a turret press leads to less consistent charges than no baffle at all. If you like to weigh every charge and constantly adjust your powder dispenser, then by all means, go nuts.
 
hAkron said:
Well then use if it makes you happy, I was just sharing my personal experience that showed that using the baffle on a turret press leads to less consistent charges than no baffle at all. If you like to weigh every charge and constantly adjust your powder dispenser, then by all means, go nuts.
Click to expand...

Weighing every charge defeats a weak reason for using a turret press. But, then, I cannot figure out any advantage for using a turret press.

Currently I am experimenting with two baffles in the measure on my L-N-L progressive. No baffle or one baffle did not provide the performance I expected. The second baffle is about 1 inch above the first and installed 90 degrees to the first. So far, so good.
 
Well then use if it makes you happy, I was just sharing my personal experience that showed that using the baffle on a turret press leads to less consistent charges than no baffle at all.
Click to expand...

That may well be your experience with one brand of powder measure on one brand of press, no one is doubting that. However, that does not mean all presses behave that way.

When I use the RCBS Uniflow (which is the PM under discussion here) it is my experience that the baffle and the extra vibration help. True, there is no vibration when the Uniflow is mounted separately. This is why it helps to add the vibration using the "knock-knock" technique as discussed above. As for powder measures on progressives, you obviously haven't seen my Dillon 550 operate. :p

All the best. ;)
 
OK...got the pistol drum...went to auto parts store for dry graphite...took it apart, cleaned it with gun scrubber... and basically used a graphite caked Q-tip and rubbed it all over the drum. Re-installed...put baffle in cross ways. Hard to test yet...ran some AA#2 for some 45 acp and that stuff is like sand. Metered perfectly however. I did run some ViHt N320 and experienced a little binding on the down stroke. I'll give you all some more feedback when I do some more.
 
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