Electronic scale

[wills]

Electronic scale
Our match director/webmaster forwarded this e mail regarding an accuracy problem. Thought it might be of interest.

I purchased from Cabela’s in 2003, one of their EG 1500 Digital Scales. Recently for some unknown reason a weighed some cast 45-70 lead bullets a second time, THAT WAS A MISTAKE!. The second time around the weights varied as much as .4 grains from the first session. Upon consulting the operator’s manual, I found a small section on the back. under a conversion chart, that says the scale is accurate to 0.45 grains. The ad in Cabela’s catalog states “ Precise to the nearest 0.10 of a grain over its entire 1,500-grain capacity.” I contacted Cabela’s and asked them about the difference between their printed claim of accuracy and the manufacturer’s printed claim of accuracy. David, the product associate that I talked to, said he would do some checking and contact me the next day. I asked that he call at 5pm Texas time (4 pm their time). The next day at 6pm Texas time, I called David, since he forgot to call me back. He said he had contacted the manufacturer and they told him the accuracy was .3%. That equates to 3 full grains if you happen to shoot a 1,000 grain bullet. David tells me that the ad does not say the scale is accurate to the nearest 0.10 grain, but that it is “ precise to the nearest 0.10 grain“. After a short session between the word precise and accurate, we moved on. He says that the ad is being reviewed to determine if it needs to be changed. I don’t believe he ever used the word “corrected.“ He didn’t admit that the wording in the ad is misleading, because the ad says “precise” not “ accurate” to the nearest 0.10 grain. I wonder how many of their other ads are “accurate”. In between calls to David, I performed a small test check using three different caliber lead bullets and the two checks weights supplied with the scale. The biggest surprise was that over a 30-40 minute session, the weights generally increased. The largest increase was with a 50 caliber lead bullet that started in at 772.8 grains and ended up weighing 774.0 grains. That little bullet gained a full 1.2 grains just waiting its turn to be weighed. If you have purchased one of these scales, and have noticed similar results, you might want to contact Cabela’s. If you aren’t one of the proud owners, you still might want to contact them if you think this ad is misleading and let them know just that. Please forward this to all that might be interested. The only way to correct this kind of advertising is a show of numbers. Thank you.

[felix]

A better criteria, in my opinion, would be the accuracy of repeatability, and not of absolutes. Yes, I would like to know if my powder weighs 6.7 grains or 6.8 grains, but I really don't care unless I am selling the powder. I do want to know that everytime I weigh that powder (with the exact volume) that it does weigh 6.7 +/- 0.01. That tolerance figure is the one that should be emphasized to the hilt. ... felix

[Dale53]

Most electronic scales benefit from turning them on twenty minutes ahead of "using time". It allows things to "normalize". From that point on, a good electronic scale will weigh consistently. Your scale may just need to be warmed up before use. This is an opportunity for you to try this and report your findings to us (help us fill in our knowledge base).

Pre-warming the scale is a bit of a pain in the tuckus, but not really that difficult to do. You just have to think ahead a bit. FWIW, I use an RCBS electronic scale and will tell you that if I had to go back to a balance scale to weigh bullets I would stop weighing bullets. If you are after maximum accuracy with cast bullets (in a rifle that routinely shoots under a minute of angle) weighing is mandatory. I do NOT weigh pistol bullets nor bullets for a rifle that shoots over a minute of an angle. As an example, I weigh every bullet for my 1/2 minute schuetzen bench rifle, I do NOT weigh bullets for my Marlin 1895 45/70 that shoots 1 1/2" groups.

Dale53

[Lee]

The auto-turn-off feature on some of these scales makes the 20 minute rule a REAL pain in da butt.
Many scale makers include a disclaimer "that weights should be checked regularly against a beam scale, to insure continued "accuracy".
There are differences between the definition of precision and accuracy, I disremember what.
I load conservatively, and an electronic scale is great to tell me my charge is within .2-.3 grain, quickly and easily. If I was loading max weights, I'd be a lot more careful. And of course even an electronic scale will spot the difference between 6gr. and 11g. (telling me that something has changed!).........Lee

[MGySgt]

I use the Lyman 1200 DPS II - While I do not trust it to 'Throw a charge' and then drop it into a case, I do find that it is great for throwing a charge a few 10's under and then trickle up on a balance beam. I transfer the powder to the balance beam pan and hit the button to 'Throw' another charge. While I am in the process of trickling up the charge on the balance beam, the next charge is brought to within a 10th or 2.

The weight it states is correct in accordance with my redding balance beam. It just doesnt know when to stop on the correct 10th.

Weighting bullets - I would neve do it on a balance beam, but routinely do it on the Lyman electronic.

Warm up? I don't turn it off.

Drew

[Blacktail 8541]

I used to only weight boolits on a balance beam scale to check for gross weight error. Now that I have a pact I use it check for 1/10th grain variations on target loads and load work ups. I like to take out any uncertainty that I can during load work ups. I also weight cases during load work ups but not for general reloading.