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Posted: 9/20/2016 6:46:36 PM EDT
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I'm a little stumbled but figured the hive would know best. I've already settled on a charge of 42.2gr of imr4350 for my 260 Remington. I use a RCBS Chargemaster to get close. pour in my mechanical scale to confirm
charge. and then use the trickle function on the chargemaster to get me to my desired weight. Sometimes when the charge would get overthrown by the chargemaster (i throw 42.0gr as it tends to read a little light) say 42.2gr. I would throw it on the 5-0-5 scale to see how close we are, it would end up still being low. I would trickle to my 42.2gr and for some reason it seemed to much just by eyeballing. I would zero out my mechanical scale and my needle would need adjusting. sometimes as much as 2 rotations to get it to read level. I would throw the same charge as before and would read heavy. take it off again, confirm balance and it would need re-adjusting. The only thing I can think off that would cause such problems is the Chargemaster interacting with the magnets in the mechanical scale.(assuming it had internal magnets), Or the fluorescent lights that sit about 4 feet above the 5-0-5 scale. Any other areas to look for when trying to figure out why the scale wont hold a consistent balance? Thanks Bryan Seda |
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I would first check the knife edges on the beam for dirt and dings. Then the agates the beam rides in. Dust and dirt can cause erratic readings in a beam scale.
Make sure there is no breeze on either scale and the electronic scale may be affected by nearby fluorescent lights. I would make sure the beam is clean (knife edges and agates) and level, then check them against a set of check weights for repeatability. Beam scales are pretty much bullet proof as long as everything is clean and in good shape. |
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Mechanical scales are accurate as hell.
They must be placed on a level surface and zeroed. The scale is set at "0" grains and the scale base height is adjusted until the swing arm reads zero every time you rock the pan. The scale can't move once zeroed or you'll have to zero it again. No dirt or dust can be allowed to collect on the unit. Scale check weights are a good investment. No fans can be running anywhere near the unit. Develop a consistent pan technique and stick with it. If you always lift the pan a little to get it swinging then do it that way every time. If you lower it a little to start it swinging then stick with that technique. You can gain or lose at least .1 grain by switching your technique up. Canned air is useful for cleaning the pivot points. I trust my old RCBS 5-0-5 more than any cheap electronic scale. You have to spend upwards of $200 on an electronic just to match the consistency of a good "old school" scale. I have an old Redding scale that isn't magnetically dampend and it will register movement adding just one kernel of powder. |
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Thanks to all that have replied. I believe my inconsistency was due to dust being in the swing arm candle. However I did throughly wipe off any part that moves and ended up being consistent after the wipe down. Something I'll look into more when things begin to act goofy
Thanks again Bryan Seda |
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Amen on covering the scale. I use the stout box top that came with my Hornady Cam-Lock Trimmer...foil covered and double cardboard...perfect fit without having to break down the scale.
On this issue of taking care of the scale between uses, I have a question on the 505. If it's in the booklet, I missed it. Should the scale be disassembled when not in use...left in its zeroed state...or left "heavy" so it doesn't move? It seems to me that it's still a question related to the OP's thread here since it's a 505 and may affect accuracy and operation. |
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It's also useful to cut off single pieces of wire as check weights for your favorite loads. I have a 6.3 grain piece (roughly a 3/8" piece of 12 gauge uncoated ground wire) that I use to verify my 45 load w/ unique, for example. Great way to safety check your scale for pretty much no money.
I check the charges by progressive is throwing every time I refill the primer tube. First 5 charges get weighed, and I track the process control with SPC control charts. 
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Quoted:
I'm still trying to figure out why you are not using the Chargemaster to dispense the charge. It will easily dispense a charge within it's own +/-.1gr advertised accuracy. Mine does. Motor This. I crosscheck my charge master all the time on my RCBS 5:10 scale and it is always dead nuts on. Depending on the climate inside my house I usually only get about 5 to 7 overcharges on it. I always have it plugged into a noise canceling strip and I use a brass insert on the tip of the drop tube versus the McDonald's scrawl trick. I used to use the McDonald's straw trick and that worked just about as well. |
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I used a small (1') level to check the true level orientation of my bench. Although I thought it was level from L to R when I built it, it's actually only level when I move the level about 30 degrees from the wall.
I made a 90 degree sharpie mark on the bench, and that's where I orient the scale before zeroing. |
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On my 10-10 once I drop the charge and it settles I "bounce" the pan slightly with my finger and let it settle again. it almost always reads higher than the first time, so I usually throw a light charge which turns out to be right on after the bounce. I've used check weights to make sure it reads correctly bu just dribbling the powder in slowly doesn't seem to produce the same reading as when it has to balance from larger extremes... |
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I was having issues the other night and almost gave up, but then I whipped out the instructions to make sure I didn't miss anything.
Turns out it was the edge that that pan holding loop rides on. I try to use mine at eye level and the back of the loop wasn't in the right place and I couldn't see it. I checked the pivot at least three times, but it was the pan end. |
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Quoted:
This. And do not leave the beam on the pivots indefinitely. Set the beam in front of the scale and pop a shoe box over the parts. Quoted:
When not in use a beam scale should be covered to keep it dust free.
This. And do not leave the beam on the pivots indefinitely. Set the beam in front of the scale and pop a shoe box over the parts. That one comment was what I was curious about in my other post...the condition to leave the beam of a 505 in when not boxing it up for long term storage. I've been taking the beam off of mine when not in a session and figured it couldn't hurt...and always covering it with a box. I reread my instructions that came with the 505, and mine has no mention about this, so thanks. |
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