question????

[cockercas]

just sat loading a few cartridges up and it got me wondering, why do we weigh the charge instead of measuring by volume .

if you seat the bullet deeper/shallower you change the pressure inside the cartridge when fired.

so if you weigh charge a to 30gr and it fills up 80% of the case and you weigh the next charge the same but the powder grains weigh slightly less and fills the case 82% then there is less empty space in the case there for higher pressure. making a slightly different poi (not at 100m)

so wouldn't ammo be more accurate if it was weighed by volume .

cartridge makers load by volume rather than weight.

[roughshooter]

Blackpowder shotgun cartridges were and still are measured by volume

[cockercas]

Blackpowder shotgun cartridges were and still are measured by volume

correct but i was referring to modern powder.

[Vince Green]

When you measure by volume using a scoop the way that you do it can vary the charge. If you drive the scoop deep into the powder aggressively you will be forcing the powder into the scoop and almost compressing the charge. If you just skim it along the top of the powder you will be picking up a much looser charge with less powder in it. Make a scoop and then tap it gently a few times and you will see the powder settle. Try it.

 

Consistant scooping technique goes a long way to reducing the variables but it is an art that has to be learned. Weighing the charge has to be more consistant because you are always going to get the same amount of powder each time.

Edited April 28, 2012 by Vince Green

[cockercas]

When you measure by volume using a scoop the way that you do it can vary the charge. If you drive the scoop deep into the powder aggressively you will be forcing the powder into the scoop and almost compressing the charge. If you just skim it along the top of the powder you will be picking up a much looser charge with less powder in it. Make a scoop and then tap it gently a few times and you will see the powder settle. Try it.

 

Consistant scooping technique goes a long way to reducing the variables but it is an art that has to be learned. Weighing the charge has to be more consistant because you are always going to get the same amount of powder each time.

good answer, but when you way it on scales you still have the variable. depending on how the powder is settled in the scale pan. i tried it yesterday. i weighed a charge to what i was loading. then i taped the pan on the table a couple of times and weighed it again, it was different.

i was expecting a few more replies from the pw reloading experts. but since Ackley has been banned there names have stopped appearing in this section.

[Andy H]

How can a set amount of powder in a scales pan change weight by just tapping the pan unless some powder is lost when you tapped it , Also in handgun caliber reloading most of the reloading setups use a volumetric measurement system as weighing every charge would be impracticable due to the amount reloaded.

Edited April 29, 2012 by Andy H

[bedwards1966]

I won't claim to be an expert, but in the absence of many replies I'll voice my thoughts.

Vince Green has it right, powder might be compressed and this will give different reading. If I weigh out 40g of powder and make a round with it, and ring you up and ask you to do the same, they will be identical. If we measured it by volume, I'd be pretty certain they'd be different, because you'll dig the scoop in harder, you'd tap it off or scrape it differently - they'd be different.

 

As to the weight changing when you've tapped the pan - I would guess it's evened out the load, made it level and in the middle of the pan. When I weigh powder I'm careful to keep it all in the middle, and I often give the pan a slight shake to level it out.

 

Also imagine how many different dippers you'd need - my simple set of scales will do everything from 0.1 grain up to 109 grain, covering anything I'm ever likely to need. How many different scoops/measures might I need for an equivalent set-up, do a wide range with 0.1 grain increments?

[cockercas]

How can a set amount of powder in a scales pan change weight by just tapping the pan unless some powder is lost when you tapped it , Also in handgun caliber reloading most of the reloading setups use a volumetric measurement system as weighing every charge would be impracticable due to the amount reloaded.

simple. more powder at the back of the pan makes the scales register a heavy charge, more at the front makes it register a lighter charge.

i know what your getting at with the dippers. i was more thinking about powder throwers.

[cockercas]

I won't claim to be an expert, but in the absence of many replies I'll voice my thoughts.

Vince Green has it right, powder might be compressed and this will give different reading. If I weigh out 40g of powder and make a round with it, and ring you up and ask you to do the same, they will be identical. If we measured it by volume, I'd be pretty certain they'd be different, because you'll dig the scoop in harder, you'd tap it off or scrape it differently - they'd be different.

 

As to the weight changing when you've tapped the pan - I would guess it's evened out the load, made it level and in the middle of the pan. When I weigh powder I'm careful to keep it all in the middle, and I often give the pan a slight shake to level it out.

 

Also imagine how many different dippers you'd need - my simple set of scales will do everything from 0.1 grain up to 109 grain, covering anything I'm ever likely to need. How many different scoops/measures might I need for an equivalent set-up, do a wide range with 0.1 grain increments?

 

not so. i think that the few accidents there is with reloading are due to people not setting scales up properly.

my measured 12.3gr might be your 12.5gr and someone else's 12gr.

[wymberley]

How can a set amount of powder in a scales pan change weight by just tapping the pan unless some powder is lost when you tapped it , Also in handgun caliber reloading most of the reloading setups use a volumetric measurement system as weighing every charge would be impracticable due to the amount reloaded.

 

The following only applies from my point of view if we're talking balance arm (beam) scales. This has not been defined.

 

 

That was a potentially interesting point raised by Cockercas so I thought I'd try it. I'm still using my father's scales by Ohaus and haven't a clue how old they are. Fortunately, I live in a village with your local friendly chemist's and although we're (well, late father and myself) on the third one they must do a hand-over brief as we still get a calibration check done as a favour. I wondered why, if this phenomenon was correct, the powder pans weren't made in an inverted cone shape. Then I realised that it didn't seem possible as the contents of the pan wherever located, the down force still acted through the pan's attachment point to the arm which is a constant. Nevertheless I tried it to the extreme and got no change at all. However, what can easily occur is if you trickle in the last few flakes (to avoid confusion with the two grains) until you hit the marks, taking the pan off and replacing it will often give a higher reading. This is due to balance friction and is most noticeable at the lower end of the charge weight. Now, as I only weigh for Hornet, I do this for every load. Sitting here miles away I can't be certain, but tapping the pan may have had the same effect as lifting it off and replacing it.

[Harnser]

I suggest that you stick to factory ammo .

 

Harnser .

[Vermincinerator]

simple. more powder at the back of the pan makes the scales register a heavy charge, more at the front makes it register a lighter charge.

i know what your getting at with the dippers. i was more thinking about powder throwers.

 

I have never heard that before, 50grns of powder will be 50grns of powder no matter where its placed on the pan.

If your scales are reading different weights depending on the position of the powder in the pan i suggest you need a new set of scales or there is some kind of operator error goin on.

 

Ian.

[cockercas]

The following only applies from my point of view if we're talking balance arm (beam) scales. This has not been defined.

 

 

That was a potentially interesting point raised by Cockercas so I thought I'd try it. I'm still using my father's scales by Ohaus and haven't a clue how old they are. Fortunately, I live in a village with your local friendly chemist's and although we're (well, late father and myself) on the third one they must do a hand-over brief as we still get a calibration check done as a favour. I wondered why, if this phenomenon was correct, the powder pans weren't made in an inverted cone shape. Then I realised that it didn't seem possible as the contents of the pan wherever located, the down force still acted through the pan's attachment point to the arm which is a constant. Nevertheless I tried it to the extreme and got no change at all. However, what can easily occur is if you trickle in the last few flakes (to avoid confusion with the two grains) until you hit the marks, taking the pan off and replacing it will often give a higher reading. This is due to balance friction and is most noticeable at the lower end of the charge weight. Now, as I only weigh for Hornet, I do this for every load. Sitting here miles away I can't be certain, but tapping the pan may have had the same effect as lifting it off and replacing it.

i was loading hornet while thinking about it, and lifting the pan off the scales to tap it on the table. altho not always giving a higher reading.

i did try it to the extreme, and piled the powder as far back as i could. it did register a higher charge, but i had also took it of the scales to do it. so its inline with what you are saying

 

I suggest that you stick to factory ammo .

 

Harnser .

good answer

 

 

 

 

 

 

 

cock

 

I have never heard that before, 50grns of powder will be 50grns of powder no matter where its placed on the pan.

If your scales are reading different weights depending on the position of the powder in the pan i suggest you need a new set of scales or there is some kind of operator error goin on.

 

Ian.

see a couple of post above.wywberley comment about removing the pan

[MiLisCer]

i was loading hornet while thinking about it, and lifting the pan off the scales to tap it on the table. altho not always giving a higher reading.

i did try it to the extreme, and piled the powder as far back as i could. it did register a higher charge, but i had also took it of the scales to do it. so its inline with what you are saying

 

 

good answer

 

 

 

 

 

 

 

cock

 

 

see a couple of post above.wywberley comment about removing the pan

 

You need to buy a better scale or learn to use in properly - it does not matter where in the pan the charge is - it will weigh the same - unless you are using **** scales.

[cockercas]

You need to buy a better scale or learn to use in properly - it does not matter where in the pan the charge is - it will weigh the same - unless you are using **** scales.

read a couple of posts up about removing and replacing the pan.

[Vermincinerator]

I read wymberlys comment about lifting the pan and replacing it never heard such rubbish. Scales are designed to accurately weigh charges of powder, if a 50grn charge has been balanced on a beam scale, removed togehter with the pan, put back and the scale no longer balances, then there has been either some loss or addition to the charge, there is a fault with the scales or some kind of operator error has occurred, simples

 

Ian

[cockercas]

so there's no loss/addition

there's no operator error (im not sure what error could be made in a simple processes)

and the scales arnt broke. (its the same weight charge when loaded with 43gr varget removed and put back on)

load 12.2 gr of h110 and remove and replace and it weighs slightly more.

[wymberley]

I read wymberlys comment about lifting the pan and replacing it never heard such rubbish. Scales are designed to accurately weigh charges of powder, if a 50grn charge has been balanced on a beam scale, removed togehter with the pan, put back and the scale no longer balances, then there has been either some loss or addition to the charge, there is a fault with the scales or some kind of operator error has occurred, simples

 

Ian

 

Well, aren't you the lucky one! - and there will only be one - the owner of a mechanical device which is totally friction free!

 

Between now and my post, I have just loaded a batch of hornet rounds. If I slowly trickle in the last bit of the charge until the graduated lines align and then gently lift the pan and replace it after the arm has dropped, with the full charge weight overcoming the friction I consistantly get a 0.1 grain over reading.

 

Please also note, I expressly mentioned Hornet and the lower end of the charge weight, eg, 12.3 grains.

 

Edit: Spelling typo

Edited April 29, 2012 by wymberley

[Vermincinerator]

Well, aren't you the lucky one! - and there will only be one - the owner of a mechanical device which is totally friction free!

 

No not friction free but equal consistant friction

 

Ian.

[wymberley]

No not friction free but equal consistant friction

 

Ian.

 

The correct term for that is an, "irritant".

[al4x]

This is one of the weirdest threads on here for a long time. 50 grains is 50 grains wherever you put it on proper scales, hence calibration weights are always the same otherwise there would be no point having them or worrying about calibration. However back to the start and volume vs weight there is a direct correlation which is how powder throwers work. Mine is within 0.1 grains most of the time and I weigh every charge so should know

[cockercas]

Well, aren't you the lucky one! - and there will only be one - the owner of a mechanical device which is totally friction free!Between now and my post, I have just loaded a batch of hornet rounds. If I slowly trickle in the last bit of the charge until the graduated lines align and then gently lift the pan and replace it after the arm has dropped, with the full charge weight overcoming the friction I consistantly get a 0.1 grain over reading.Please also note, I expressly mentioned Hornet and the lower end of the charge weight, eg, 12.3 grains.Edit: Spelling typo

what load are you loading 35gr?

 

This is one of the weirdest threads on here for a long time. 50 grains is 50 grains wherever you put it on proper scales, hence calibration weights are always the same otherwise there would be no point having them or worrying about calibration. However back to the start and volume vs weight there is a direct correlation which is how powder throwers work. Mine is within 0.1 grains most of the time and I weigh every charge so should know

yes i know its the same, but not so on the scales that was part of my point on the volume vs measuring. there's still variables.

also what thrower are you using?

[al4x]

RCBS and a set of their beam scales. With varget I find its pretty rare to get an incorrect charge possibly 1 in 15 gets thrown back in.

[dicehorn]

Re volume v weight. There are other variables regarding volume, I use a powder dropper for all my calibres - that decreases the volume and affects pressure. I also weigh all cases and segregate/batch them - that also affects volume and affects pressure. So, for me weight is everything

[MiLisCer]

read a couple of posts up about removing and replacing the pan.

 

Yes I read the above post and dismissed it. A decent set of balance scales produces consistent results - ok, if you are running safe loads then the result is not critical - but when running hot loads the results are critical - when I started reloading I used to double weigh - then I bought some better scales - now I know that the weight will be correct.

 

Just as an aside, I loaded 200 hundred 308 rounds last, no I did not double weigh them all - but every now and then I did out if curiosity take the pan off the scale - tap it, shake it, move the load to one end - guess what? yep you have guessed it - it weighed exactly the same when it went back on the scale.

 

Maybe it is because I know how to read and use my scale correctly? maybe because I look after it, keep it dust free? or maybe just luck? hmm - no it is because a decent set of beam scales for reloading is designed to be consistent and accurate.

 

Mike