Lee and RCBS powder scale inaccuracy...

[Shooter98]

So I bought the Lee challenger kit a week back and love it, but I decided to verify the grain weight of the scale vs. a trued digital scale. With the Lee scale set at 49 grains the digital scale was showing 44.8. That's a huge difference!

I decided to go back through the instructions for zeroing out the scale once again and retried. Again, the digital was showing about 4.5 grains less than the Lee.

I went to my buddies and took the digital scale with me. We tried it against his RCBS scale. It was off by 1.8 to 2.5 grains.

This would explain why my load data said I should be pushing 3200 fps but when I chrono'd my loads they were 2940 fps.

I then used the digital to check bullet weights. It was dead on. The Hornady Vmax 75 grains all scaled out at 75.1 to 75.3.

I think I'll stick to using a digital scale from now on.

Anyone else have similar results?

 

[RT2506]

That is the reason that they have check weights so you can calibrate you scale. In my experience it is a stretch to say that the Lee scale would make a good paper weight. Never had any problem with my RCBS beam scale. It is right on the money.

 

[Shooter98]

That is the reason that they have check weights so you can calibrate you scale. In my experience it is a stretch to say that the Lee scale would make a good paper weight. Never had any problem with my RCBS beam scale. It is right on the money.

I didn't get a check weight with the Lee scale. Obviously the certified digital scale has a 100 gr weight.

 

[Kevin Thomas]

A cheap scale is a cheap scale, whether it's digital or beam. As RT2506 said, that's why we have (and hopefully use) check weights. I have more issues with digital scale, as I've seen plenty of them that would hold adjustment, wouldn't weigh accurately and defied attempts to correct them. Again, they were cheap ones. Among the less expensive svales, I think the beam type tend to be more accurate and trouble free, but they all need to be checked, zeroed and rechecked from time to time.

 

[Topgun 30-06]

Kevin---As a retired State of Michigan W&M Investigator with over 30 years experience, I have to agree with you 100%. I use an OHaus beam scale and if a beam scale is taken care of they will last a lifetime and match or exceed accuracy of any of these lower priced digital scales they are selling nowadays.

 

[Shooter98]

Kevin---As a retired State of Michigan W&M Investigator with over 30 years experience, I have to agree with you 100%. I use an OHaus beam scale and if a beam scale is taken care of they will last a lifetime and match or exceed accuracy of any of these lower priced digital scales they are selling nowadays.

I can definitely see a high quality beam scale to be the cats meow. Unfortunately, I think the market has more lower quality cheap scales readily available. The digital scale I use is a fairly expensive cerified scale that included a cerified weight. I feel I can trust it right now much more than my beam scale.

 

[Topgun 30-06]

Don't know why you are putting my quote up and then making a response that you have an expensive digital scale. That was not what was mentioned in our discussion. By the way, what are you calling a "certified" scale? When the term "certified" is used in weights & measures it means that the device has been tested by a W&M Official and meets all the requirements of Handbook 44. A certified scale would normally be one that is in use in a commercial operation where buying and/or selling takes place, not one used to weigh gun powder!

 

[Shooter98]

Don't know why you are putting my quote up and then making a response that you have an expensive digital scale. That was not what was mentioned in our discussion. By the way, what are you calling a "certified" scale? When the term "certified" is used in weights & measures it means that the device has been tested by a W&M Official and meets all the requirements of Handbook 44. A certified scale would normally be one that is in use in a commercial operation where buying and/or selling takes place, not one used to weigh gun powder!

Sorry, what I was quoting was that a good beam scale is the best option for the most part. Yes, you're correct about the cerified scale, it's part of my wifes business.

 

[BountyHunter]

There is a guy named Scott Parker that tunes beam scales for around $20 and shipping.

Read about him at 6mm Br about 3/4ths the way down the page.

BLOG July 2006

BH

 

[CogburnR]

I have checked my el-cheapo lee against other scales and with weights and it is dead nuts on. I would trust a beam scale before a digital. I have seen digitals creep pretty fast with a temp change.

 

[Topgun 30-06]

I would definitely go with a good beam scale over any of these cheap digital scales with my years of knowledge on this subject. The main thing is to not let them swing free other than when they are in use for the weighing process. Keep them locked in place if they have that feature, or an alternative is to put some weight in the pan so the beam isn't in motion other than when in use. That way the V area (knives in W&M lingo) where the beam sits does not wear out. They should be almost sharp for good, accurate weighing. The guy that was mentioned probably replaces those when he does a repair/service job as it's easy to do.

 

[Trickymissfit]

So I bought the Lee challenger kit a week back and love it, but I decided to verify the grain weight of the scale vs. a trued digital scale. With the Lee scale set at 49 grains the digital scale was showing 44.8. That's a huge difference!

I decided to go back through the instructions for zeroing out the scale once again and retried. Again, the digital was showing about 4.5 grains less than the Lee.

I went to my buddies and took the digital scale with me. We tried it against his RCBS scale. It was off by 1.8 to 2.5 grains.

This would explain why my load data said I should be pushing 3200 fps but when I chrono'd my loads they were 2940 fps.

I then used the digital to check bullet weights. It was dead on. The Hornady Vmax 75 grains all scaled out at 75.1 to 75.3.

I think I'll stick to using a digital scale from now on.

Anyone else have similar results?

when I got my Ohaus 304 scale the guys down in the gauge inspection room where I worked at told me everyone the company owned had been rebuilt by them! They were gauged against a $10K digital scale that was kept in a clean temp controlled enviourment. I brought mine in for a check up, and it was better than most of the ones they'd checked. They did some adjustments, and we were good to go. One thing we did find out was that the three calibration weights were off a little bit. All were heavy a little bit, and they also brought them into spec. I also did the same thing with three electronice scales I've owned, and they were pretty much good to go right out of the box. But the weights were not good enough to get the best calibration. (one was off .25 grain)
gary

 

[Trickymissfit]

I would definitely go with a good beam scale over any of these cheap digital scales with my years of knowledge on this subject. The main thing is to not let them swing free other than when they are in use for the weighing process. Keep them locked in place if they have that feature, or an alternative is to put some weight in the pan so the beam isn't in motion other than when in use. That way the V area (knives in W&M lingo) where the beam sits does not wear out. They should be almost sharp for good, accurate weighing. The guy that was mentioned probably replaces those when he does a repair/service job as it's easy to do.

knife edge bearings are very prone to false brinel in any application. It's the nature of the beast, and as long as you have it in an enviourment with anykind of vibration you are damaging the knife edge. If you have the scale in any building with electrical current; then your running a 60Hz vibration accross the bearing surface 24/7. But if you could keep the scale moving on the bearing surface 24/7 the problem would be very remote. Made lots of money rebuilding them
gary

 

[Topgun 30-06]

You completely lost me when you threw in electricity in the mix and that having them in motion 24/7 shouldn't bother them. Do you tell that to all your customers you make a living from, LOL?