RCBS Beam Powder Scale and calibration weight questions

I have the same a Lyman test weights and load from 2.5 to 30 grains with the majority under 10 grains. Both of the digitals I have and 4 of the 5 beam scales all are on with those test weights. I have had the Lyman weights for many years so don’t know if that makes any difference. Do you know anyone that you could try them on their scales to see what the outcome is?

Say hello to the March Hare. Trust the weights.

I have a Pacific powder balance, which is a beam scale without any graduations. Set it up, exact level is not required. Put the desired weight on the pan and adjust the beam to zero, replace the weights with powder, adjust powder til the beam balances at zero.

Balance is 80 yrs old and is all I used for 20 yrs. Last year I bought a set of RCBS weights to check the duralumin weights that came with the balance and they were right on. I don't mind the settle time, and use my thumb and forefinger on the pointer to help it settle faster.

So, no need to become unhappy with your scale. You can use your scale the same way, put the desired weight on the scale and use the poise to get close, if not right on, use the calibration thumbscrew as a vernier to zero.

I bought an inexpensive Lyman pocket scale to weigh bullets and brass, because that can't be easily done on a beam balance. So far it is in cal, works well as long as I put it in the environment I intend to use in for at
least 2hr (garage or house) turned off, and use fresh batteries.

Clean the knives and pivot points with an alcohol pad and try again. My Redding scale is very accurate but fussy about being clean.

.40

Pat Riot said:

5 grain test: Main poise at 5 grains, small poise at Zero - 6 gr ... Main poise at Zero, small poise at 5 grains - 5.5 gr

10 grain test: Main poise at 10 grains, small poise at Zero - 10.5 gr ... Main poise at 5 grains, small poise at 5 grains - 10 gr

Should I not trust the Lyman weights and trust the M500 scale or should I do something different?

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I would trust the check weights and distrust the scale that's reading inconsistently.

If you want further verification, you can buy another set of check weights that goes down to .15 gr (10 mg) to test sensitivity of the scale:

• One set for $15 - https://www.amazon.com/American-Wei...coding=UTF8&psc=1&refRID=VW7SHP1YDXZ1WNA5J5SE

• Another for $12 - https://www.amazon.com/Bekith-Preci...CCPQJCJ7AKA&psc=1&refRID=2JHSM8R5XCCPQJCJ7AKA

Pat Riot said:

1. Is an RCBS M500 the wrong scale for measuring really light pistol powder loads?

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No. Think about it. Reloading scales were made with .1 gr resolution and designed to weigh "really light pistol powder loads" to load 380Auto, .32 and even .25 caliber rounds that require powder charges down to 1.5 to 2.0 grains.


So if the beam scale meant to be used for reloading is not reading down to .1 gr consistently, I would first focus on checking the scale for cleanliness and wear before thinking it is not appropriate for reloading. (And proper usage is key to repeatable zero and consistent readings so make sure the bench top/scale is level and there is no air movement around the scale)

Pat Riot said:

2. Is there a scale you can recommend for light powder loads?

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Sure, ANY scale that can detect and repeatedly verify .10 gr (Or even .15 gr/10 mg) check weights whether it is new beam scale, used beam scale or digital scale (regardless of price of $17 to $700).

And what are examples of those scales? Dillon Eliminator beam scale made in USA, Lee Safety Scale made in USA, Used Ohaus/RCBS 10-10/5-0-5 beam scales made in USA, A&D/Ohaus/Sartorius digital scales made in USA, AWS Gemini-20/WAOAW digital scale made in China that can all verify check weights down to .10/.15 gr.

Pat Riot said:

3. Should I trust the Lyman calibration weights?

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Check weights can become less consistent depending on how it was used and stored. If not handled by forceps, oils/sweat from hands and environment could corrode/add weight over time.

Pat Riot said:

Right now I don’t. I found that the 5 grain individual weight is .5 grains off compared to using 2-2 grain and 1-1 grain weights.

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You don't know that. What you do know is that readings you are getting from the scale are inconsistent. For me, I rather trust more the check weights that were stored/handled improperly.

Like I already posted, if you have any doubts, get yourself another check weights ($12/$15 shouldn't break anyone's bank) to verify both your scale and your current check weights.

Pat Riot said:

4. Should I buy another scale like a digital or another beam scale to compare with the M500 or replace the M500?

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I would first spend $12/$15 for another set of check weights and re-verify the scale after a through cleaning and making sure the bench surface is level and away from air movement by closing doors/windows/vents.

Pat Riot said:

5. Should I look at digital vs beam scales?

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See my answers for #2 and #4.

Pat Riot said:

6. Am I heading down a rabbit hole?

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No. You are asking questions based on new information THR provided to you.

You are simply getting your eyes opened to true reality of accurate and consistent measurement down to .1 gr resolution.

Pat Riot said:

I was looking at digital scales this morning and they all use 50 gram weights for calibration. Many of the reviews mention “an excellent 0.2 grains of accuracy”.

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Sure, and everyone says, "I do" when they get married to stay and be committed through sickness and health but they lie, cheat and end up divorced ... Don't believe the advertised claim.

Pat Riot said:

I was going to try to bring my Lee Precision scale into my testing to compare it to the M500 and the Lyman weights

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Excellent idea as Lee Safety Scale actually has better than .1 gr resolution and comparable in detecting .05 gr like my two Ohaus 10-10 beam scales.

Pat Riot said:

7. Am I being to picky, anal, analytical, whatever...in this regard?

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There are some people who simply want to "reload" usable rounds for their guns as hobby and there are some people who want "handload" greater consistency/match grade rounds for their guns as passion.

forty_caliber said:

Clean the knives and pivot points with an alcohol pad and try again. My Redding scale is very accurate but fussy about being clean.

.40

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Yes x2 on that. Works wonders. Q-tips and alcohol.

Search this forum for beam scale recalibration. Search for Beam Scale 101 by Project255. Really worth a read.

Usually.... knife dressing is not needed. Clean is needed, not only for the knives/bearings, but for the notches for the weights.

Next - make sure ZERO is ZERO, that there is no wind or air movement, and that the scale does not move on the surface it was zero'd on.

At that point... if the check weights were truly calibrated, each range scale be measured independently. The best way to do this is to sort the check weights for close to the maximum each range scale will measure. That is to say, if you have a 5grain and a 500grain scale set up the check weights to measure just under 5 grains and just under 500 grains. When "testing" one range, the other range should be at zero weight.

Beam scales are linear. Using truly calibrated check weights, if you're over or under at a point on the scale that is close to its maximum range, the notches on that range control the linearity, and there's not much you can do if those notches aren't right. Fortunately, they very seldom aren't right.

Lets say your 5 grain scale, calibrated in .1 steps is heavy. You put in 4.5 grains of check weights, but the scale zeros at 4.1 grains. You'll need to remove a tiny bit of weight from the poise, until it zeros at 4.5 grains. If it's light, reading for instance... 4.9 grains, you'll need to add weight to the poise. Removing weight on small poises is done by filing a TINY BIT and rechecking. I've found that a drop of super glue will add the weight needed. If the poise is a metal blade....you can snip off the smallest bit of a corner to remove weight.

Same is true for the bigger scale that goes to 500g, but... many scales (and I think the RCBS M500 does this) have an adjustable poise with a set screw that moves the weight within the "holder" portion of the poise. Try that before adding or removing weight from the poise.

In either case, remember to RE-ZERO when you adjust a poise, then go back and remeasure the same check weight amount to see how your adjustment did. Its not uncommon to overshoot (for me at least, but then again I'm anal about it). That's ok, you can scrape off some dry super glue, or add some if you removed too much material.

When you get the scale reading well at almost full range, then its linearity (the equal spacing of the notches) are the determining factor for its overall accuracy. Again, not uncommon to see minor variation along the entire length of the scale, but at that point, it is what it is... and you gotta live with it.

And you can go read that whole..... very long thread, and see more info.

Pat Riot said:

Project355 said:

You put in 4.5 grains of check weights, but the scale zeros at 4.1 grains. You'll need to remove a tiny bit of weight from the poise, until it zeros at 4.5 grains

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I just realized the pan holder is weighted with lead shot. Perhaps I made a mistake when setting up the scale.

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Before you change the lead weight in the pan holder, I would first verify the scale is consistently reading zero.

Even though the pointer is not pointing at zero mark, is the pointer returning to the SAME spot each and every time?

If so, then with Ohaus/RCBS beam scales, you simply adjust the foot so the pointer is at zero mark. (If your scale pointer is not returning to same position, you need to clean and use level surface until it does before changing pan holder lead weights)

Let's say your scale is zeroing at the same spot every time (Picture exaggerated for effect) like below but not at zero mark



You adjust the foot so the pointer points at zero mark

Pat Riot said:

@Project355
I just realized the pan holder is weighted with lead shot. Perhaps I made a mistake when setting up the scale. I will have to go through the set up procedure again and verify I weighted the pan holder (?) properly.

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Read the long, long article on beam scales.

The weight is part of the pan/pan-support and is a constant. The lead shot makes it such that slight variations in pans, supports can be made to work. Other scales have a wire support and those are "trimmed" (clipped) at the factory to get it such that the scale will zero out at about half way through its travel, while on a dead level surface. Most surfaces are not dead level, and that's why there's an adjustment screw.... you can level the scale while its on a slightly tilted shelf or bench/table top.

With a CLEAN scale, if you can zero it, its good to go as far as pan weight is concerned. Again - all the accuracy is in the beam, and just how even they cut those notches. They can be machine cut, or cut on a die that was machine cut. Its very rare to see the notches out of kilter. As long as the poise is the right weight, and reads correctly against a known weight that is almost full range, then the scale is as accurate as its ever going to be. The graduations control the accuracy. Very minor adjustments to the poise may be needed for the most very anal-retentive of users.

On a 0-5grain range, the markings and notches are in .1 increments. Putting .1 or .2 grains in the pan is useless. Put darn near 5 grains in there, and then see what the scale reads. Go on from there, see if minor tweakage is needed. If its dead-nuts on at, say, 4.5 grains, then the amount of error at .1 grain is going to be nil, beyond the resolution of the instrument. You'll be darn near close to right on the money at any range from 0-5 grains.

I'll say that on the scales I've recently messed with, only the large range was off, and in those cases it was off by .2 grains or so close to the max range. Very very careful adjustment is needed, but workable, but for most, who cares if you're off by .2 grains at 485 grains? In most instances, it matters not. All the short range poises were dead on the money - except a Redding that needed very very slight adjustment.

Pat Riot said:

I have an RCBS M500 beam powder scale that I have been very happy with until yesterday.
You see, I went to my reloading store last week and I bought a set of Lyman calibration weights. I actually bought them because I always buy something when I go to my reloading store even if I am just there to see if he got primers in. I want to keep him in business and I didn’t have any calibration weights so...

Anyway, I used these weights yesterday and found that when using the scale at low charge weights for handgun cartridges I have some discrepancies after zeroing and checking Zero several times in this process

5 grain test:
Main poise at 5 grains, small poise at Zero:
6 grains of weight to balance beam.

Main poise at Zero, small poise at 5 grains:
5.5 grains of weight to balance beam.

10 grain test:
Main poise at 10 grains, small poise at Zero:
10.5 grains of weight to balance beam.

Main poise at 5 grains, small poise at 5 grains:
10 grains of weight to balance beam - Dead On.

So, here are my questions:
1. Is an RCBS M500 the wrong scale for measuring really light pistol powder loads?

2. Is there a scale you can recommend for light powder loads?

3. Should I trust the Lyman calibration weights?
Right now I don’t. I found that the 5 grain individual weight is .5 grains off compared to using 2-2 grain and 1-1 grain weights.

4. Should I buy another scale like a digital or another beam scale to compare with the M500 or replace the M500?

5. Should I look at digital vs beam scales?

6. Am I heading down a rabbit hole?

I was looking at digital scales this morning and they all use 50 gram weights for calibration. Many of the reviews mention “an excellent 0.2 grains of accuracy”. I don’t see that as “excellent”. Not when I load 9mm 115 grain loads with 4.9 grains of Universal and the Max recommended by Hornady is 5.0 grains. I want accuracy in my handgun loads. I load WAY more handgun cartridges and I use mostly Universal powder. My loads range from 4.3 grains to 7.7 grains of powder depending on what cartridge or bullet I am loading and for whichever gun.

I was going to try to bring my Lee Precision scale into my testing to compare it to the M500 and the Lyman weights but then I remembered what a PITA that things was to set and discarded that idea.

Last question:
7. Am I being to picky, anal, analytical, whatever...in this regard? I do not think so.

Bottom line is:
Should I not trust the Lyman weights and trust the M500 scale or should I do something different?

Thank you for reading all this.
PR

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Zero your scale to 10 grain check weight then re test your scale

P.R , yes zero or check weight your scale to as close as you can to the charge you intend to use . I would never just pick a weight and zero my scale to that and think for a second it will be dead on at every weight . These are cheap scales that are not “that” good in the grand scheme of things. Go spend $1k on a scale and maybe you’ll be able to set it and forget it .

I even re-check weight my scale at intended charge every 30 or 40 rounds loaded as well . My Redding beam scale is pretty good for the price but seems to drift +\- .1gr through out a loading session. Seeing how the scale is only good to +/- .1gr , include the drift and it’s only good for +/- .2 gr if not double checked every so often through out the loading session.

I use a powder balance, not the same as a scale. That said, use your combination of calibration weights to make up the desired powder charge. If you want 47.6 gn or 5.4 gn, put that combination of weights in the pan and use the poises to get close, then use the knurled screw/knob scale adjustment to zero the scale. Note the poise positions so you can see if they move when you move the pan.

Set your powder measure to drop a charge, in the pan, that balances (zeros) the scale, and you have the correct charge. Believe the weights, before believing the scale. If the scale is set to zero with no weight in the pan, then the powder is added to the pan until the scale reads zero it will be the correct weight no matter what the poises on the balance beam say.

My powder balance is my golden reference against which I check my electronic scale. I have a new, never used Lee balance beam scale because I find it harder to use than my Pacific Powder Balance.

PWC said:

Say hello to the March Hare. Trust the weights.

I have a Pacific powder balance, which is a beam scale without any graduations. Set it up, exact level is not required. Put the desired weight on the pan and adjust the beam to zero, replace the weights with powder, adjust powder til the beam balances at zero.

Balance is 80 yrs old and is all I used for 20 yrs. Last year I bought a set of RCBS weights to check the duralumin weights that came with the balance and they were right on. I don't mind the settle time, and use my thumb and forefinger on the pointer to help it settle faster.

.

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For anyone not familiar with PWC's strange machine, here are a couple I have. I'm surprised this idea is not more widely used - it's almost fool proof.


And a couple of my homemade efforts:

1066 said:

For anyone not familiar with PWC's strange machine, here are a couple I have. I'm surprised this idea is not more widely used - it's almost fool proof.

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My Pacific Powder Balance is like the second one pictured, the black one, it is 83 years old, still accurate, and foolproof as long as the pivot arm is centered.