Weighing Powder

[Cherokee]

Long post. Looking for some insight. I've been reloading since 1957. Started with a beam powder scale from Redding, then switched to a Lyman beam scale until about 1998 or so when I bought a PACT electronic scale. I always used the scale to set my powder measures for specific charges. Vast majority of my loading data was developed with the Lyman beam scale, which I found out weighed a specific charge slightly (1-2%) less than the PACT. I retested the old data (that I was still using) with the PACT data and all was OK. Have developed new data using the PACT as the "standard". Then the PACT went flakey in January and I sent it back to PACT. While waiting I bought another electronic scale from Midway. Got the PACT back after a month and now all three of my scales give me different weights. Using the 20 gram check weight, which should be 308.8 grains, I get 303 on the Lyman, 308.3 on the cheap Midway and 309.1 on the repaired PACT (when it settles down enough to give me a consistent reading). When I get down to the more practical levels, 7-42 grains, I get extreme variances between the 3 of 7%. I am having a problem with confidence in either of these scales. Most of my data is not pushing Max but some is close enough that I don't want to get any closer and a few are Max. I guess my question is how do you develop trust in your weighing device, or do you have any comments to help.

[littlejack]

Cherokee:
I don't knbow if this will help but this is what I use and have used since I started loading 45 years ago. I have a OHAUS M-5 beam scale. Very accurate. If I want to check it (just for kicks, I put a match bullet on it to weigh. That is close enough for me. The scales' "0" can be adjusted with an up and down screw. I assume as with most scales of decent quality. I do not see any reason to get closer than that. These scales are still available on flea-bay, and if something was to break on the ones I have, it would take me all of about 60 seconds to get another just like it. I would not hesitate.
Where you are going to have the problem, (if you do not weigh each charge) is the powder measure. Some of them will vary quite a bit, depending on the type of powder used in them.
Jack

[Lead Fred]

The reason I dumped my RCBS electronic scale was that it was not stable.

I use a 30 year old RCBS 10-0-10 and a 40 year old Redding. They test out within 2/10ths of each other.

[mike in co]

for 98% of reloaders, std beam scales are just fine....
as you have seen with three scales, you get three answers.
these scales are typically plus or minus 0.1.
plenty good for plinking and hunting, and target work with factory guns.

plick one scale and use it...the beam would be my choice and the electronic for sorting boolits.


if you want more consistancy, spend more money.

my mx123 from denver scales was $325 and is plus or minus 0.02 with 0.03 sensitivity.

ya spends yer money and ya takes yer chances.

the beam scale works when it moves and then settles, if you trickle up and the beam is not moving up and down...it may provide a false low reading/high actual in the pan.

mike in co

[Cherokee]

Thanks for the input. One thing I saw was the variations would change depending upon the weight - smaller charges had less % variation, larger charges had larger % variations. I did buy a new RCBS beam scale that arrived today (after I started this post) and it come much closer to the two electronic scales @ 308.5 for the test weight and for several other weights tested on the 4 scales. Looks like I will junk the old Lyman which always has the lowest weight. I did try to adjust the Lyman beam counter weight last week to get closer to the test weight but then it would not zero with no weight.

My powder measures do real well (Dillon, RCBS & Lachmiller) with the powders I use, mostly ball but it was the scales I set them with and check the throws with that worried me. With 3 scales now that weigh close, I feel much better. I don't mind spending the money but was not aware of the denver scales. I'll keep that in mind for the future.

[Mk42gunner]

When I was in the Navy, living on board ship or in the barracks; I used to load at a couple of friends houses. Knowing their scales weren't technically calibrated; I bought a set of RCBS scale check weights to ensure my powder charges were at least somewhat close to what the scale said.

That $20 has bought a lot of piece of mind over the years.


Robert

[cajun shooter]

I have owned the PACT, and RCBS electronic scales. Pact makes them both. They were very sensitive to wind or other close by electronics including fluorescent lights.My 1010 scale that I have had for over 20 years remains my solid verification station. I have a set of check weights and it is still correct. About two years ago I decided to buy this electronic scale from a seller on Flea-bay. It sells for $29. I thought that I had paid well over $150 for the other scales why not try the cheap ones. Well I now have three of them and they all work perfect. They are called DigiWeigh and are sold by one man who ships free also. I don't have a dog in the hunt and I will not post his name as people may think I'm trying to make money. What I am saying is that you can buy a $30 scale that works. They come with check weights and they weigh in grains, carets,grams and oz's.

[Cherokee]

cajun - I have seen them and wondered if they were any good because of the cost. Good to know they work.

Mk42 - I have check weights: "I get 303 on the Lyman, 308.3 on the cheap Midway and 309.1 on the repaired PACT" which is what drove me to the questions since they should all have given me 308.8 as the answer. The new RCBS is much closer and will be my standard.

Thanks again everyone.

[1hole]

"They were very sensitive to wind ..."

All sensitive scales are sensitive to wind.

[c3d4b2]

At work we check our measurement devices for accuracy and repeatability (called a gage R & R study) for the lowest reading we would want to detect If we are wanting to detect a 0.1 grain measurement we would weigh 5 samples that weigh 5.0 grains through 5.5 grains multiple times (generally 3 times, with a random order) to determine how repeatable the measurements are. We then will calculate some statistics to determine the source of the variation with the different personnel involved in using the interments.

I do not know if this level of analysis is required, but it might be a good idea to take some repeated measurements to check the scales repeatability.