In order to participate in the GunBroker Member forums, you must be logged in with your GunBroker.com account. Click the sign-in button at the top right of the forums page to get connected.
Options
Can't be too careful
Ambrose
Member Posts: 3,164 ✭✭✭✭
I had an interesting experience this morning that could have turned out very bad. I've been reloading since 1958 so I'm not exactly new at it. At the range yesterday, I tried a load in a 700 Remington in .222 Rem. that showed promise so I thought I'd try it again today. The load consisted of 55 gr. Sierra blitz, 19.7 gr. of IMR4198, RP case, and Federal match primer. I loaded 10 cartridges last night (weighed every charge) intending to fire two 5-shot groups today. The first shot across the chronograph screens read 3400 fps! I was expecting 2975 fps. Everything seemed normal--no hard bolt lift, no smoke from the action, primer didn't fall out or seem excessively flatened. But I'm running a 5-screen chronograph system with both an Oehler 35P and a PACT so I'm getting 3 readings and they all agree so I believed the chronos and quit right there. I remember a trick I heard of a while ago where you can get an idea where you're going velocity-wise by dividing your velocity by grains of powder to get fps per grain to determine how much powder you need to get the velocity you're after. Doing the math indicated it would take 22.5 grains of IMR4198 to get to 3400 fps. NO WAY I could have made a mistake of 2.8 gr.!!! Fortunately, my reloading set-up was just the way I left it last night. I pulled a bullet and went to weigh the powder. I use a RCBS 505 scale. The 10's gr. weight was not quite in the notch! When I settled it in the notch and weighed the powder--22.5 gr.!! Why my outfit held together with that much of an overload, I'll never know! One more thing to double check.
Comments
This is one reason why I went to a digital scale, I kept having under-charged loads so the dials and beams just didn't seem to me to be right on. The digitals (to me, anyway) make it easier to get it spot on and there's no guessing about the weight...(provided your scale is on target, of course)
I also like it for weighing bullets, cases, etc. I was suprised at the weight differential in differing brands of brass....
In any case, good call on stopping when things aren't right![8D]
ditto on the digital scale.
Me three [;)]
Every charge had balanced perfectly - but not at the eight grains I wanted. Thirteen.
Thinking back, I can't imagine how I'd not noticed that the powder filled the case. But when I pulled the bullets, every single one of them did.
Right now they have a Hornady 1500 for $29.00.
http://www.cabelas.com/product/Hornady-GS-1500-Electronic-Scale/1156191.uts?Ntk=AllProducts&searchPath=/catalog/search.cmd?form_state=searchForm&N=0&fsch=true&Ntk=AllProducts&Ntt=electronic+scales&WTz_l=Header%3BSearch-All+Products&x=13&y=6&Ntt=electronic+scales&WTz_l=Header;Search-All+Products
I've also caught myself many times changing the scale for something then going back and throwing a charge and finding it way off. As noted above when I returned the weights, one didn't seat at the bottom of the intended notch. Sure enough the powder load was suddenly way too high or low. That's when I decided all changes got checked with test weights. They are the only known constant out there.
A second scale is better as it allows you to verify the powder weight is correct. Measure twice.
Check weights would have verified the accuracy of the scale, but in this case as one the sliders wasn't in the slot, a check weight wouldn't have made a difference unless the check weight was the weight of the charge he was dropping.
A second scale is better as it allows you to verify the powder weight is correct. Measure twice.
Exactly, Check weights are a known quantity. Except, in this case the weights WOULD have caught the error. Another scale might have been just as wrong.
If you are not familiar with check weight sets, they come in denominations that allow you to check any load right down to half of a grain. You used to be able to get sets that are accurate down to .1 gr.
http://preview.tinyurl.com/9rqbarr
http://preview.tinyurl.com/6tq8t8x
My scales only came with two check weights, unless you have a weight set that has multiple weights that can get a exact weight such as 22.5 grains as Ambrose posted.
A second scale is still not a bad idea and to have two scales read the exact same wrong weight is a very small possibility.
The two links I gave you are check weight sets that can give you exact loads, in most cases, up into the 50 gr. weight range.
But, I see what you are saying and that is a single check weight of say 40 gr. is used to test the scale each time you set it up. You then change the scale settings to the desired weight.
In the OP's case, the two scales happen to be just the same. But what if one is two-three gr. lower than the other? Which one is correct? You don't really have a known quantity to go by. The check weights give you an exact load amount on your scale no matter what the scale says. And they cost about $30. Much less than a new scale does.
I caught the weight not quite in the slot recently and it alarmed me.
If they were V notches that possibility wouldn't exist.
You probably wouldn't have the combination of check weights to verify each exact weight of powder. Therefore, a check needs to be made to see the weight is seated in the notch every time the scale is adjusted.
Anyway, I've not embraced this new "digital" tech as have many of you....I like my digital scale, but I always check it with my balance scale...sort of opposite of what most of you do!!