Powder Measure Accuracy

[xdmKevin]

I have a dilema for anyone using Lee products!
Im using lee auto disk that is suppose to be 5.7 grains. Im using win 231
Its measuring at around 5.2 grains on the cheap lee beam scale.
Its measuring at 5.4 grains on my Lyman digital 1200 scale.

Which measurment is the closest to being the right measurement? I just got the auto disk for my new turret press yesterday and I dont know how accurate it is yet. My Lyman and the Lee beam scale have always been about .2 grains apart and I have adjusted as needed in the past.

Thanks in advance for any help from those familiar with these scales.

 

[Uniquedot]

I have the Lee scale and three digital scales as well as a Lyman 1000 beam scale. If your showing .2 difference i am willing to bet you can blame the digital scale every time. As long as you know how to properly adjust and use the Lee (and can stand the damper wait) you can trust the Lee scale to deliver accuracy.

 

[xdmKevin]

Thanks for the quick reply, I agree with with the digital scale part of the beam scale being more reliable. Do you have any experience with the lee auto disks?

 

[LiveLife]

Do you have any experience with the lee auto disks?

Yes, happily been using Pro Auto Disk for the past 16 years.

I just rechecked the zero on my Ohaus 10-10 beam scale and weighed two different check weights (they were spot on).

I placed the .53 disk hole (Lee Auto Disk chart indicated for 5.7 gr drop of W231) on the Pro Auto Disk and cycled 6-8 times to make sure the powder was settled in the hopper (I usually do about 3-4, but wanted to make sure for this check). The next 10 drops were consistent at 5.5 gr. BTW, I double checked the drops on my old FA DS-750 digital scale and it indicated 5.5 gr also (it also verified the weighs of the two check weights).

For me, it's been my experience that Pro Auto Disk drops are often .1-.2 gr on the lighter side depending on the powder/lot used.

 

[xdmKevin]

Thank you that is great info for me to know, I knew it had to be slightly off but was unsure exactly how much.

 

[TommyD45]

You probably should get your own set of check weights and check the accuracy of the scale you are using to measure the charge actually dropped with your disc and your powder.

I don't know how tight the manufacturing tolerances are for the Lee disc or for the 231 powder. It is possible that there could be enough variation from lot to lot in either the powder density (grains/cc) and/or the actual volume of the Lee auto disc, that it would make using somebody else's calibration data incorrect.

Checking it yourself on your own particular setup will be more accurate.

You can find check weight made by RCBS or Lyman at Midwayusa.
http://www.midwayusa.com/viewProduct/default.aspx?productNumber=493216

Tom

 

[Epoxyoyo]

I never could be my Lee scale to act right so I put it on the shelf and got a 5-0-5. Best thing I ever did.

 

[LiveLife]

You probably should get your own set of check weights and check the accuracy of the scale you are using to measure the charge actually dropped with your disc and your powder.

+1 on the check weights. I absolutely agree. BTW, Ohaus 10-10 and FA DS-750 scale came with check weights.

And this is the reason why I tend to use mid to high range load data instead of max load data. If there exists some variations in powder weight/lot variation, I have some "buffer" room towards the max load data. If I am loading at max load data, I don't.

On top of this, I also keep in mind that Glock's hexagonal rifled barrels tend to generate higher velocities (chamber pressure) than the conventional land/groove rifled test fixture barrels.

If you see deviations in your measurements from the published data, I highly recommend that you calibrate/verify your equipment accuracy, just in case. Better safe then BOOM.

 

[Tim the student]

FYI, a dime from after 1965 will weigh almost exactly 35 grains. A brand new one will have less wear etc.

 

[RidgwayCO]

For our reloading friends who don't READ THE INSTRUCTIONS, I've captured this information off the Lee Pro Auto-Disk instruction manual (included free of charge with each Lee Pro Auto-Disk, and available for download from the Lee website).

"Weighing Charges - Maximum Loads Must Be Weighed

If you check charges on a scale, be sure to take one out of a normal loading sequence. This is especially important when the measure is used on a Turret Press as the powder packs in during the other loading operations.

Powder densities can vary more than 16% and still be considered within tolerance by the powder manufacturer. (This means the disk cavities will probably NOT dispense exactly what the chart says, since the chart is designed to be conservative and therefore assumes the powder you're weighing is on the densest extreme.)

For safety reasons, you will frequently find charges less than those listed on the charge chart. However, should you find one that is 5% more than the listed load we would like to know about it.

Note: Coarse flake powder, such as Red Dot and Green Dot (and Unique), can give light charges in the smaller cavities. ( .40 or smaller ).

Charge in grains x VMD Factor = Volume CC"


I believe this answers most of the questions about the Lee Auto-Disk measures. Don't worry, I've copied the information presented to my computer and am ready to re-post it as many times as necessary to avoid all of the retyping...

I don't mean to sound flip or condescending, but do people REALLY create potentially deadly devices, which do their business mere inches from the user's face, without reading anything about it? Personally, I find that a touch terrifying...

 

[brickeyee]

FYI, a dime from after 1965 will weigh almost exactly 35 grains. A brand new one will have less wear etc.

When you are interested in 0.1 grains, a dime is not going to cut it.

Buy some check weights.

 

[Tim the student]

When you are interested in 0.1 grains, a dime is not going to cut it.

If you thought I was suggesting that they are a good substitute as check weights, you are mistaken. But, they are ok to use as a down and dirty (and probably - hopefully for that matter - less accurate) reference when you have nothing else available.

 

[twofifty]

do it yourself checkweights

I agree with Tim and will raise the ante:

an assortment of coins makes a half-decent set of checkweights,
IF you get a pharmacist to weigh them on a dispensing balance.
Then convert grams to grains.

A few small washers and other tiny metal parts readily available from a hardware store are suited to the lighter range of measurements, like powder.

Just drop that dime or washer on your scale, move the beam weigths till the beam balances. Your beam scale reading should match your pharmacist's reading to 0.1 gr.

If you keep your home-made checkweights clean, dust & grease free in a plastic box, you're GTG.