I've got a "like new" RCBS 5-0-5 scale and a new electronic scale off of eBay. I'd like to make sure they both work with accuracy before I start dumping powder into my prepped cases. I've seen a few check weight sets on the web at greatly different prices, but would like to know if any of you would recommend any particular brand or set.
Recommend calibration check weights
- Thread starter satexas
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An adequate check weight won't even cost you a penny. Either of your scales are only accurate to +/- .05 grain. A copper zinc penny (new type) weighs 2.500 grams according the the US mint. 2.500 grams = 38.580 grain. Weigh a penny and you should get 38.6 grain. Check google for various US coin weights.
You don't need scientific scale accuracy to load accurate ammo.
You don't need scientific scale accuracy to load accurate ammo.
Reefinmike
Member
I just weighed out some pennies. Saw a spread over 10 from 38.2-38.8gr. I wouldn't use pennies for check weights.
Reloadron
Contributing Member
Originally posted by bds:
Really depends on how accurate you want to get and what resolution. Steve C pretty much called it. I have a RCBS set I use and like, RCBS #98992.
Ron
Really depends on how accurate you want to get and what resolution. Steve C pretty much called it. I have a RCBS set I use and like, RCBS #98992.
Ron
rabid wombat
Member
I would research what is required for your set. The RCBS system uses a pair of 50g weights (I think) for their calibration (check to confirm!).
For scales and weights, these guys are great! I bought a counting scale, and it works like a champ. Good people and honest service!
http://www.oldwillknottscales.com/calibration-weights-sets.html
For scales and weights, these guys are great! I bought a counting scale, and it works like a champ. Good people and honest service!
http://www.oldwillknottscales.com/calibration-weights-sets.html
I have the Lyman set and use it EVERY time I reload. I use to figure out if I need to calibrate the CM1500s and also I bracket the load to make sure that all is good. When I bought the set quite a few years ago, I checked the weights using a $10,000 Mettler Toledo lab grade scale and I was very impressed with the quality of the Lyman weight set. Here's my original thread from 2009.
http://www.thehighroad.org/showthread.php?t=433321
http://www.thehighroad.org/showthread.php?t=433321
sellersm
Member
Another recommendation for the Lyman set.
rcmodel
Member in memoriam
If you have access to certified precision scale at work??
Don't waste money.
Make your own check weights out of copper wire or paper clips, cut to near weight with wire clippers, and fine tuned with a fine-cut file, or emery paper on the end.
I made mine at work 40 years ago on an Ohous scientific scale in the lab.
And I'm still using them.
Realistically you only need a few.
2.5 grain, and make 4 of them. (2.5, 5.0, 7.5, and 10.0 combined)
10.0 and make as many as you like.
Maybe a 25, 50, and 100 for quickly adding weight for checking bullets & cases scale range.
rc
Don't waste money.
Make your own check weights out of copper wire or paper clips, cut to near weight with wire clippers, and fine tuned with a fine-cut file, or emery paper on the end.
I made mine at work 40 years ago on an Ohous scientific scale in the lab.
And I'm still using them.
Realistically you only need a few.
2.5 grain, and make 4 of them. (2.5, 5.0, 7.5, and 10.0 combined)
10.0 and make as many as you like.
Maybe a 25, 50, and 100 for quickly adding weight for checking bullets & cases scale range.
rc
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rcmodel, you have an excellent idea! I work in a metallurgy/failure analysis lab and also have access to all kinds of metals from beryllium to tungsten, as well as grinding and polishing equipment. The Mettler balance is at least 5 places and should do the trick for making my own. Why didn't I think of that?? 
rcmodel
Member in memoriam
Well, sometimes I can't see the forest for all those dang big trees in the way either!!
Sometimes 'outside the familiar box' thinking is all it takes for me to think, OMG, why didn't I think of that!!! :banghead:
Let us know how it turns out!!
rc
Sometimes 'outside the familiar box' thinking is all it takes for me to think, OMG, why didn't I think of that!!! :banghead:
Let us know how it turns out!!
rc
I made a few by grinding down various bits of broken drill bits. I made a few that were exactly what I was using for a drop on a couple different cartridges. My theory was even using a beam scale I could use my check weight to make sure it really was balanced at a specific drop.
Of course they are only as accurate as the scales I used to make them. So I checked lengths vs weight as I ground them down and used a drill bit that required a discernable length ground off to make a change. It wasn't difficult to figure out how much to take off to hit the middle of band.
In any case whatever they weigh, they weigh the same every time. So if they are off .05, it's good enough for me.
I also have a set of lyman weights and some misc. gram weights.
Of course they are only as accurate as the scales I used to make them. So I checked lengths vs weight as I ground them down and used a drill bit that required a discernable length ground off to make a change. It wasn't difficult to figure out how much to take off to hit the middle of band.
In any case whatever they weigh, they weigh the same every time. So if they are off .05, it's good enough for me.
I also have a set of lyman weights and some misc. gram weights.
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I have an older Lyman check weight set. I weighed each weight on a precision scale and they are exact weight except for one weight that is 2 tenths of 1 grain heavy. Very near perfect. I highly recommend a check weight set and can only recommend Lyman's set from experience with it.
Most cartridges have less than a 10 fps change in muzzle velocity for each 1/10th grain change in charge weight. 4 to 8 fps is the norm. Can you measure velocities consistently to that level?
There's a greater spread in muzzle velocity caused by the tiny chemical differences across several powder charges with exactly the same weight (to 2 decimal places) than a 1/20th grain error in laboratory spec charge weight measurements.
Hand holding a rifle chronographing loads will show a 3 to 5 times extreme spread in velocity as well as SD numbers than if the barreled action was clamped solid in a fixed mount and doesn't move back in recoil while the bullet goes through the barrel. There's easily a 50 fps or greater spread in average velocity across several people shooting the same load in a given rifle. Same across several rifles shooting the same load by one person.
Short range accuracy matches' winners and record setters meter charge weights to a 2/10ths grain spread. They get 1/4 MOA average accuracy doing so. Sierra Bullets meters powder to a 3/10ths grain spread getting the same accuracy in unprepped cases with their best match bullets.
It's important that your scale is repeatable. Doesn't matter if it's 2/10ths grain off from an expensive lab spec check weight. There's a greater spread in the fps a given powder lot will produce because each production lot of it will need more than that much change in charge weight to match what another lot produces for given muzzle velocity numbers. Weigh some bullets then use them for check weights. Each one should have the same weight each time its measured.
There's a greater spread in muzzle velocity caused by the tiny chemical differences across several powder charges with exactly the same weight (to 2 decimal places) than a 1/20th grain error in laboratory spec charge weight measurements.
Hand holding a rifle chronographing loads will show a 3 to 5 times extreme spread in velocity as well as SD numbers than if the barreled action was clamped solid in a fixed mount and doesn't move back in recoil while the bullet goes through the barrel. There's easily a 50 fps or greater spread in average velocity across several people shooting the same load in a given rifle. Same across several rifles shooting the same load by one person.
Short range accuracy matches' winners and record setters meter charge weights to a 2/10ths grain spread. They get 1/4 MOA average accuracy doing so. Sierra Bullets meters powder to a 3/10ths grain spread getting the same accuracy in unprepped cases with their best match bullets.
It's important that your scale is repeatable. Doesn't matter if it's 2/10ths grain off from an expensive lab spec check weight. There's a greater spread in the fps a given powder lot will produce because each production lot of it will need more than that much change in charge weight to match what another lot produces for given muzzle velocity numbers. Weigh some bullets then use them for check weights. Each one should have the same weight each time its measured.
Bart is right, repeatability is the most important thing. My measure might throw an average 44.8 and yours an average 44.7 and shoot exactly the same. If my scale says 44.8 and your 44.7, it's OK, as long as the next time out you repeat what you have been doing that works for you. Consistency.
And heck yes, a check weight that is .01 grains off is the least of our worries. I know, we like things to be perfect, but perfection is tough. We need to accept that very small variances in weighing or measuring powder are not the issue when we shoot a big group with a known proven load/rifle. It's almost always our fault. 99% or better. Sure, sometimes a scope goes bad or gets loose on occasion, but blaming equipment is usually a waste of time and energy.
Assuming a good load/rifle, it's the loose nut behind the trigger 99.99% of the time.
Yes, I have some check weights, and I use them, but gave up on absolute perfection weighing powder a long time ago.
MCMXI has the right idea, and his linked thread is a good read. Repeatability with your components and equipment.
And heck yes, a check weight that is .01 grains off is the least of our worries. I know, we like things to be perfect, but perfection is tough. We need to accept that very small variances in weighing or measuring powder are not the issue when we shoot a big group with a known proven load/rifle. It's almost always our fault. 99% or better. Sure, sometimes a scope goes bad or gets loose on occasion, but blaming equipment is usually a waste of time and energy.
Assuming a good load/rifle, it's the loose nut behind the trigger 99.99% of the time.
Yes, I have some check weights, and I use them, but gave up on absolute perfection weighing powder a long time ago.
MCMXI has the right idea, and his linked thread is a good read. Repeatability with your components and equipment.
spitballer
Member
I agree with rapid wombat, oldwillknottscales has a great site with chat services. Also I've learned not to argue with Bart B, and I suspect that his assertions about super-accurate weighing are probably in the end more correct than some of us would like to acknowledge.
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