Scale Test Weights

[Twoboxer]

The most important thing about checkweights for reloading is that they be relatively close to the weights you are looking for. EG, if you are going to weigh 5.0 grain charges using 50 gram cw (~150 times the weight) is pointless. There's no guarantee your scale's performance is linear.

Using a 52 grain bullet as a cw is equally pointless since you can guarantee it does not exactly weigh 52 grains.

Using a NEW US coin seems doable until you weigh a bunch of them and see the variation.

HOWEVER, if you can weigh any one of those on someone else's CALIBRATED scale you can have an excellent cw . . . as long as you keep it clean.

The RCBS cw's are a good set. They are not certified as meeting any particular standard (which is what makes other cw's so expensive) but they are within hundredths of a grain of their nominal weight and that is close enough. The standard set gets down light enough to check your scale for powder throws, and combined with your GRAM calibration weights seems sufficient.

 

[Nemo288]

Agree with others about using something close to your charge weights.
The 5 and 10 grain weights are the ones I use most often to gain confidence.
The RCBS set has fulfilled that function for years for me along with the
heavy calibration weight that comes with most scales (use that one first every time).
Very few bullets I have weighed (pretty much all of the 44's) are right on the to the .1 grain.
The Woodleigh and Swifts are there but also cost more than $1/bullet.
Whats important is that a box all weigh the same and that doesn't always happen either.

 

[Clovishound]

One thing to consider. When you weigh a powder charge, you are not weighing, say 5 grains. You are weighing 5 grains plus the container, be it the powder pan that comes with the scale, or the case, if you tare the case then throw powder. I know you will see the difference displayed, but the actual amount weighed will be the total of the two.

 

[Nemo288]

I zero the scale WITH the powder container on it and THEN use the check weights.
You are trying to verify the actual charge as used with a known weight.

 

[reddog81]

I have 3 cheapo digital scales - Frankford Arsenal, MTM and another. The only problem I've had is the scale driffting when the batteries were low. I use 2 scales to verify each other. If one says 42 grains and the other says 42 grains i'm pretty sure whatever is being weighed is 42 grains and they cost less than $40 each.

 

[Clovishound]

I was thinking the process would be to use a check weight of known weight to check the accuracy of the scale. For instance, a quarter weighs close to the amount a .357 case, with primer and powder. I would then zero out the scale, weigh the known quarter that is 87.5 grains. If it is on the money, then the assumption would be that say a 90 grain case with primer and powder would be accurate. I can see that checking it with a 50 gram weight might not give you as accurate a check, being almost 10 times the weight of the quarter.

Having a set of check weights that would cover the range of weights you would normally encounter would be cumbersome. I see several grain differences in the weight of cases all the time.

Adding up check weights to get to a target weight would potentially cause additive error. For example, if you are using 5 check weights to add up to the target weight, and all are .03 grains over, then they will be off by .15 grains. If the check weights are accurate to less than say .01 grains, then you will probably be fine, unless you are using a whole pile of them.

 

[Nemo288]

You may be overthinking this or "going about it the hard way" as they say.
Say I am wanting to drop a 7 grain charge.
Calibrate the scale with the heavy weight after a warm up.
This sets its linearity.
Put on the powder pan (I know how much it weighs).
Yep proper reading.
Tare or Zero the scale.
Put on 7 grains of test weights.
Does the scale say 7 grains? Yep! You are good to go.
Even more important you now have confidence in your load.
The total weight is irrelevant.

 

[AlHunt]

Why would you want check weights in Grams??

Well, that is a great question. Glad you caught it ...

 

[DWalt]

"Why would you want check weights in Grams??"

No reason not to. Just multiply grams X 15.43 to get grains. My Lyman digital scale came with a pair of gram-denominated check weights. Long ago, I had access to a laboratory balance with a precision of 0.0001 grams (1/10 milligram). I made up my own set of scale check weights by cutting and filing finishing nails to precise 10.0 grain weights, made up 10 of them, kept them in a little plastic box with my scale, anything between 10 and 100 grains could be used. I still have them. I also made up a 25.0 grain weight and a 40.0 grain weight out of .25 ACP and .32 ACP brass cases respectively, they went into the same box with the finishing nails.

Back when I first started reloading (about 1961), I had a two-pan apothecary scale I rescued from a dumpster. Its slider was graduated in both grains and grams. I used it for quite a long time to weigh powder, it worked well. I still have it, but have not used it for many years. I also have a 4-beam Ohaus damped single-pan lab scale which weighs to a precision of 0.01 gram (0.154 grains). It's great for weighing cases and bullets, segregating them by weight uniformity very quickly. It would be OK for powder weighing also, but I do not use it for that.

 

[crankyoldlady]

A range pal made a set for me. He cut pieces of aluminum from a Pepsi can that weighed 2 grains, 5 grains, and 10 grains. These were calibrated using a digital and two beam scales.

Any small item that has been thoroughly proofed can be used as a test weight.

 

[Rule3]

"Why would you want check weights in Grams??"

No reason not to. Just multiply grams X 15.43 to get grains. My Lyman digital scale came with a pair of gram-denominated check weights. Long ago, I had access to a laboratory balance with a precision of 0.0001 grams (1/10 milligram). I made up my own set of scale check weights by cutting and filing finishing nails to precise 10.0 grain weights, made up 10 of them, kept them in a little plastic box with my scale, anything between 10 and 100 grains could be used. I still have them. I also made up a 25.0 grain weight and a 40.0 grain weight out of .25 ACP and .32 ACP brass cases respectively, they went into the same box with the finishing nails.

Back when I first started reloading (about 1961), I had a two-pan apothecary scale I rescued from a dumpster. Its slider was graduated in both grains and grams. I used it for quite a long time to weigh powder, it worked well. I still have it, but have not used it for many years. I also have a 4-beam Ohaus damped single-pan lab scale which weighs to a precision of 0.01 gram (0.154 grains). It's great for weighing cases and bullets, segregating them by weight uniformity very quickly. It would be OK for powder weighing also, but I do not use it for that.

Why?

Because we deal in grains. If you want to convert every time than that's up to you.

Kinda like, why do the cheap electronic scales come with 100 gram check weight? Not even close to any standard powder charge.

 

[Jupiter01]

When I was very new in reloading, I wrote to Lyman, and inquired about check weights. I received a 21 gr. set by return mail!
Nevah happen today, I betcha! Anyway, I've used them on my Ohaus 505 scale, then my Dillon beam scale for the last 40 years or so.

I also use a 53 gr. bullet that weighs 52.8 gr, a 125 gr bullet, and a 117 gr bullet...close enough for reloading, I think.

I zero my scale with the light weights. If I am only loading handgun, check my measure's drop weight, and that's close enough. For rifle, a zero with the 52.8 g. bullet will reduce any variation in the final charge.

 

[DWalt]

Why?

Because we deal in grains. If you want to convert every time than that's up to you.

Kinda like, why do the cheap electronic scales come with 100 gram check weight? Not even close to any standard powder charge.

Do you understand the concept and purpose of a check weight? Seems you do not.

 

[Rule3]

Do you understand the concept and purpose of a check weight? Seems you do not.

Seriously? Give me a break. No ,I guess I don't.

Do you set your calipers to millimeters and convert every COL?
Are your manuals in grams?

It's a shame the USA is probably the only place that does not use the metric system.
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[flyrobb]

AMEN to that! I remember when I was young, many years ago, the talk about going to the metric system. It would be so much easier.

Seriously? Give me a break. No ,I guess I don't.

Do you set your calipers to millimeters and convert every COL?
Are your manuals in grams?

It's a shame the USA is probably the only place that does not use the metric system.
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