Reloaders -- BEWARE!

[Aguila Blanca]

Every time you use the check weight to calibrate your scale, you are introducing a scientifically-troublesome degree of inaccuracy:

https://www.scientificamerican.com/a...-the-kilogram/









[Yes, this is mentioned in some degree of jest.]

[LE-28]

Do you think a few molecules rubbing off my check weight will affect my loading scale that is only accurate to .1 of a grain?
I don't think I have anything to worry about when the equipment I'm using (scales with an accuracy rate of +or - .1 gr) has a variance of weight a million times more than the molecules weigh that is rubbing off my check weights.

That is the least of my worries.

Yes, this is mentioned in some degree of jest.

I would hope so.

[Dano4734]

What about the house fly that landed on my measure does that count:-)

[Reloadron]

Well I figure it this way. Does any of the error mentioned come in light of the intended use of any of my powder weighing scales? Following careful thought and consideration the answer is nope.

Actually this is not the first time that standards of measurements have come up for changes and it won't be the last. The calculations based on fundamental constants has been the direction other standards have taken so the kilo gram change would not really surprise me.

Ron

[gw44]

Ok then my 50g check weight should weight 15g as much as I use it !!!

[hounddawg]

The guys with the $1500 Satorius on thier benches will be sweating when they read this

[MarkGlazer]

You know, I've always wondered about the affect of dust accumulation on my scale....

[TXAZ]

That's why they make 'standards weights', traceable to NBS standards. They're not that expensive.

[hdwhit]

My balances can only reliably measure to 1/10 of a grain. A few molecules here or there have no effect.

As I was once told in college, the difference between Engineers and Physicists is that Engineers have the luxury of being able to look at the equations used to describe physical systems and decide that various parts of the equation do not have a meaningful impact on the computations. This is one of those times.

[PPGMD]

Originally Posted by hdwhit

As I was once told in college, the difference between Engineers and Physicists is that Engineers have the luxury of being able to look at the equations used to describe physical systems and decide that various parts of the equation do not have a meaningful impact on the computations. This is one of those times.

The joke I heard was a physicist, a mathematician and an engineer were taken out to the 50 yard line at local football stadium. At the end zone was the college's cheerleaders, and they were told that they can run from the 50 yard line advancing half the distance to the goal line each minute. If they make it to the goal line they will be able to date one of the cheerleaders. The physicist and the mathematician scoffed, but the engineer started running. The mathematician yelled at the engineer "What are you doing you will never reach the goal line?" The engineer replied "I can get close enough for all practical purposes."

[mikld]

Kinda like theory vs. real life. Not one of my 4 reloading scales is "laboratory accurate", but they check well against some of my standards (new coins, check weights, premium bullets). Besides, the reloading scale need not be accurate to one hundredth or even one tenth of a grain, but it should be repeatable to .010 grain...

[Nick_C_S]

I'm presuming this to be a tongue-n-cheek kinda thread.

But speaking of check weights:

I always use them to calibrate my balance scale - every loading. I calibrate to the nearest 0.5 grain to the load's charge weight. i.e. if my charge weight is 5.8 grains, I'll calibrate to 6.0 grains.

AND - I never touch my check weights with my bare hands. Hand oils are corrosive (especially mine, for some reason - if I touch a piece of copper, there will be my finger print the next day). I usually wear gloves when I load (mostly because my corrosive hand oils will tarnish my just-tumbled shiny brass); and I always use tweezers (gloves or not) to handle my check weights.

[LE-28]

AND - I never touch my check weights with my bare hands. Hand oils are corrosive (especially mine, for some reason - if I touch a piece of copper, there will be my finger print the next day)

Do you eat a lot of spicy foods? I never where gloves and I have only one piece of brass that has my finger print on it and it took 10 years to show up.

Maybe I better check my pulse.

[primerman]

Mine are still in pristine condition as they are still untouched by human hands.

[Bayou]

In the reloading world, I don't think a variation of "five parts in 100 million heavier than all the working standards" will keep me up at night worrying about my checkweights....

[Unclenick]

The change away from physical standards is, as Ron said, ongoing. It used to be a milliliter was defined as the volume of a gram water at its most dense temperature (a tiny hair below 4°C). That definition had precision issues because it depended on both accurate weight and accurate temperature measurements in combination. Later it was defined as the same volume as a cubic centimeter (a cube one-hundredth of a meter on each side) with a meter being defined as the distance light in a vacuum travels in 1/299792458th of a second. Prior to that, it was defined by a certain number of wavelengths of a krypton86 emission in a certain oscillating mode. Prior to that is was the length of a physical platinum bar. Prior to that, it was a ten-millionth of the distance from the equator to the north pole, a distance that isn't perfectly constant because the earth isn't a perfect sphere.

Well, but how precise are your check weights? Most of those sold for reloading are class 6. These are not the greatest precision available, so moving them out of tolerance by handling them is not easy. Class 0 laboratory weights are another matter.

[F. Guffey]

I have check weights, I have check weights that do not agree with each other, I guess I should expect that with anything associated with reloading.

I also have check weights that are what I consider expensive and I have check weights that I consider cheap. SO I called a company that sells check weights, they suggested I use the small tweezers when handling the check weights and the cost of the weights had to do with the material used to make the weights. And I was surprised.

F. Guffey

[Charlie98]

I would think lack of a perfectly level surface, microscopic film on the rollers, or residue build up on the beam, pan, or hanger would have more effect than a few missing molecules on the check weights...

I will file this in the appropriate place... file cabinet #86.

[mikld]

I reloaded safely with just Lee dippers and no scale, back in '69 when I was hard pressed for cash. I thought my loads varied as much as .25-.5 gr., but when I got a Lee Safety Scale I found I could actually hold .1 gr with dipping W231. Now my scales are much, much more precise (one weights to .010 gr.), but my 38 Specials of '69 were/are just as accurate and safe as my 38 Specials of today, using a digital scale calibrated in .010 grain...

[Grey_Lion]

""That's why they make 'standards weights', traceable to NBS standards. They're not that expensive.""

Well I'll tell you - the older balance scales used in the old pre 1970's chemistry classes - what many people don't know is that those calibrated weights were sometimes pure platinum.....

Not expensive he says........ keep an eye out for me for old scales at yard sales - I might pay you to ship them to me......

[Reloadron]

""That's why they make 'standards weights', traceable to NBS standards. They're not that expensive.""

During the changes in the world of metrology (measurement technology) NBS (National Bureau of Standards) is long gone, consumed by change. NBS morphed into NIST (National Institute of Standards and Technology).

Ron

[Drm50]

I've accumulated 4 sets of check weights. One is Jap and in hard case complete with tweezers to handle them. They aren't cheap junk. To a point uniformity is
more important than actual weight. The amount +or- you are going to be off isn't in capability of the scale to define. I know a guy that bought a heavy barrel
H&R Handi gun 223. His first rifle other than 22s. Decked it out with a big BSA
varible. Bought Lee loading set. He ask if I would stop by and check him out on
setting dies and walk him through a few. When I got there he was setting at the
kitchen table with Lee beam scale. He had a couple boxes of Sierra 55gr bullets
and was busy sorting out the "bad" bullets that didn't 0 out on his scale. He got
perturbed when I told him his new scales weren't up to the task and was sure that Sierra bullets were hold to higher specs than he could measure. Also his new rifle and scope rig were not in the class to take advantage of micro measurements. As in anything else tolerance is a big part of loading. You have
to ask yourself how much precision is practical for the task at hand. For my HV
bolt actions I weigh and trickle each one. For LV rifle and handguns, I drop the
charges and check every 10th one. Final check with light to ensure no double charges or short loads.

[F. Guffey]

A near-by reloader was having trouble with his Ohaus 10-10 so I suggested he bring the scales for a test run. He thought the Starrett 12" machinist lever was over kill and the note pad was not necessary but when finished the platform used with the scale was level.

I do not want for scale parts; I used my beams on his housing base with no improvement and then I replaced his base. He sent the scales back to Ohaus, they made the repairs. At the next gun show he purchases another 10-10 with a RCBS label.

F. Guffey

[Brutus]

Kilograms schmilograms, never happens with pounds and ounces.

[Sevens]

I was a junior in high school when I started handloading metallic. Mo mentor, no internet and a Speer#11 was my only source of information beyond whatever Guns & Ammo might say in any issue at the time. I loaded .38 Special and I didn't own a scale. I had a full set of Lee dippers and the Lee "slide rule" decoder thing to tell me what charge weight of which powder I was getting. This method of powder handling came because I was on an absolute shoe-string budget. It was 3 or 4 years later when I purchased my first scale, and even then it was the very low-cost (but accurate!) Lee scale.

My next scale was an ultra-low quality Frankford Arsenal digital and it sucked out loud. Rather than dink around with the check weight that came with it, I kept a 55 grain .224" SP bullet (a particular one, not grabbed randomly from a box) and once that junk scale warmed up, I would check it often with that one particular rifle bullet. When it read "55.1gr" then I knew the scale was working at that moment.

I truly have no idea if that bullet weighed 55.1 grains, but when my craptastic scale said that it did, I went forward in the process. And I loaded probably ten thousand rounds of ammo across numerous calibers doing that and I had enormous success doing so.

It didn't matter what the bullet weighed, it only mattered that it always weighed the same. All the loads I built and fine-tuned and referred back to later to re-create all ran wonderfully. They may not have been exactly the weight that I recorded on each box of ammo or in my reloading log, but every time I set up to make that load, the charge weight was the same as the one that had worked.