Problems with RCBS scale?

[boogalou]

First a little history,

Started reloading pistol ammo a couple of years ago. My Dad had some stuff inherited from my grandfather so started out with a redding scale and lyman 55 power measure. Noticed right away that the lyman measured ball powders like Bullseye & AA5 more accurately then flake powders like Unique & Clays. Redding scale worked fine. My Dad and Grandfather had used it for years.

Dad decided later that He wanted to do some reloading for his 8mm Mauser so I gave him back the redding and purchased a RCBS 5-0-2 scale. At first everything seemed ok, but lately I've noticed that I'm having a heck of a time getting the same charge when I'm checking powder weight before starting to load a batch. Of course the flake powders have been harder to keep constant weights but now I seem to be having problems with stuff like Bullseye & titegroup. Seems every time I start to weigh the powder I'm close to .2-.4 grains off from the last charge, and it takes awhile before I'm satisfied that the charge is consistant enough to use.

Is this normal or do I have a problem with the RCBS scale? I figure the powder measure is fine since this problem wasn't this bad with the redding.

Any thoughts on this problem?

 

[Joey2]

I am having the same problem with my Lee powder loader and scale. I also have a RCB scale like yours and get different measurments than the Lee.

Which scale is more accurate????????

 

[Mal H]

2 to 4 grains is a huge difference between measurings. My first suspicion is that the measure is at fault and not the scale. Scales rarely fail, but measures often do due to the mechanics of it and mostly due to powder differences.

You need to get (or make) a set of check weights. If you do suspect the scale, check weights will tell you immediately if your suspicion is correct.

 

[boogalou]

Mal - Read your post and realized that I forgot to put a dot in front of my grain differences.

That is a huge difference!

Time to edit!

 

[MaterDei]

You need to get (or make) a set of check weights.

Make? Make how? I suppose if you had a scale you knew for certain was calibrated right you would make weights on that scale. Is there any other way?

Thanks in advance.

Michael

 

[Mal H]

"... if you had a scale you knew for certain was calibrated right ..."

Exactly. Find someone with a scale that is known to be accurate (most electronic scales have check weights included) and weigh some objects of various sizes, i.e., one is around 2 grains or so, one is around 50 grains, etc. Then you have your own check weights.

Check weights do not have to be in increments of whole grains or 10's of grains to be useful. If you have an object that you know weighs 47.7 grains, that is just as useful for our purposes as an expensive check weight set that weighs exactly 10.00 grains or 50.00 grains.

 

[MaterDei]

Thanks, Mal H.

Sadly I know NOBODY who reloads and has a scale.

Maybe I should buy an electronic scale, make my own weights and return it.

Of course, I could just buy some check weights and be done with it.

 

[labgrade]

"Sadly I know NOBODY who reloads and has a scale.

Maybe I should buy an electronic scale, make my own weights and return it."



EVERYBODY who relaods absolutely must have a scale/balance/weighing device (whatever you want to call it). Anything volumetric is a disaster waiting to happen = rarely are they "calibrated" to deliver an accurate amount of powder (by weight) per their published "scales." & you cannot rely on the settigs of their micrometer adjustments for anything thrown by weight - & that's what you're looking for.

A decent balance scale will deliver accurate weights within reasonable accuracy +/- couple .2 grains. Many come with a "known weight object" for delivering extra amounts of powder & have their known weight on them. They can be useful for a zero-versus-"known weight" scenario. Not a decent calibration, but actually, close enough for who it's for.

If, by chance, you have any access to anyone who has scientific-grade equipment, you can weigh various items & record what they weigh. Touch them only with forceps so you don't transfer your finger oils to the items & change their weight.

Other than doing all this nifty stuff, you can buy a set of check weights ( perfectly suitable for anything reloading( through several distributors - cost is fairly minimal.

 

[Chainsaw]

boogalou, Your scale is probably ok. Do you have a ceiling fan in the area or a draft? This affects my scale and I would make sure to check for that problem,

I for the most part do not trust my scale to read 100% correctly. I have a 5-0-2 also and just use it as a reference point for checking my powder weight. I do have some known check weights and while my scale is close, it is not 100% perfect. Something could be going awry in your powder thrower as well.

For instance my 9mm load with 115 grain fmj's calls for up to 5.6 grains of AA#2 powder. I load to 5.1 grains measured on my scale. The load data books are a good reference point, to start with, but your own checks and balances will determine your loadings as you already know.

I think unless your are loading for a precise BR rifle, your scale should work ok, unless it has a major defect. Or your new powder lots could be a little different consistency wise from the previous containers. Anything could be possible. Let us know when you figure out what the problem is.........Chainsaw

 

[boogalou]

Chainsaw - I think the problem was I was not throwing a few charges after adjusting the powder measure. Someone on another gun board said that everytime he makes an adjustment on the powder measure, he runs a few charges through it before starting to weigh them. I tried that yesterday and it definately made a difference. I was using Unique, which doesn't meter very well in the lyman 55 anyways, so I was happy with my results.

 

[M16]

Not throwing at least five charges after changing the setting on your powder measure is probably the problem. Get a check weight. Most good quality scales come with one. Use it everytime before you start reloading and I mean every time. Anybody who doesn't use a check weight or something to verify the accuracy of their reloading scale is a damn idiot in my opinion and shouldn't be reloading. Try an electric scale. You will never go back to the balance beam.

 

[ID_shooting]

I know this is probably not the "correct" way to check your scale, but it works for me to "trust" my scale to give me consistant results. I take an empty case, zero the scale and then put the case in the pan. Adjust the scale to find out how much the case weighs and repeat the process a few times, with the same case. If you get the same result every time, I trust the scale.