Clovishound

Again, it sounds like the VMD calc merely allows me to arrive at a volume that will give me the correct weight. Therefore, the weight is the actual end result you are looking for. If volume of powder was the standard, then loading data would be given in volume not weight.

I need to understand what the ultimate benchmark is that I must compare my load to. My understanding is that it is weight. If this is not true, then I have a fundamental misunderstanding of what I should be doing while reloading.

I would be uncomfortable doing a VMD calculation, setting my powder measure accordingly then loading up without checking a number of samples thrown by the measure to make sure they are the correct weight.

tglazie

It is actually a bit of a chicken and egg thing going on. As determined by numerous tests over the years by shooters and powder manufacturers, the absolute best results are when the volume of a charge is the most consistent, rather than the weight of the charge being the most consistent. This has to do with charge density and the ability of the flame front to pass through the powder, etc.

Bottom line is that today's powder are so consistent, and we reloaders hold our charges so incredibly close vs what we need to be holding, that it doesnt make a difference which way you choose to drop a charge so long as you can repeat it as closely as needed for the given application (which as we know is usually far far more precise than the projectile will every notice, for various reasons).

Once I have a charge that works for the gun/projectile/etc, I may measure every 10, every 25 or even just once a box once I have proven to myself that the drop is consistent. The weighing of the powder is just to confirm that the powder is dropping the correct volume, not the other way around.

MZ5

O.P., I would suggest buying Lee's Perfect Powder Measure for rifle powders, and/or the Pro Auto Disk measure for pistol powders. The Perfect, despite its low price, is among the vest best of all dispensers on the market at any price in terms of consistent packing and metering of powder. I've verified this for myself in a distributed way with others over the 'net. It's not ideal for pistol applications simply because it may not give small enough charges for some (many?) cartridges.

The Auto Disk does a great and consistent job as well, even with very difficult flake powders such as Unique and similar ones. The adjustable charge bar will address most if not all issues of not having exactly the right cavity size for a particular charge or need.

On the side topic going on this this thread: I've verified for myself that using volumetric charging, rather than weight-based, results in better consistency across lot and powder age-related changes. It would be nice if others would run honest and direct comparisons of this issue, too, to foster a more-informed discussion of the topic.

Darkker

You are looking for the correct volume, but need to do the VMD for a correlation(not direct translation) to the charges in the books, which are listed by weight.


Neither way is "wrong", if there is such a thing...
Volume just accounts for the powder variations better than the weight will.
Tglazie has given a good acount on this.
When powders are on the "heavy" side of the bulk density tolerance. They are then also on the slower side of the burning rate tolerance. The opposite is also true. So over the course of lot variations, you will have less variation when using volume.

stargeezer

I used a pair of RCBS Uniflow low powder dumps for 40 years. The two had no plastic moving parts, sloppy slip-to-fit parts, or (to me) ubjectionably rough, unfinished castings. Over the years I have found all of these "issues" on various Lee products I have purchased and used.

Last year I bought my first Lyman powder dump and was thrilled by its manufacture. All the various slides moved as they should without binding, the casting job was first rate and it has worked perfectly. It is more complex than the Uniflows I own, but its multible fine adjustments will enable me to fine tune my load in a new and better way.

Please note that I do not discount the usability of the Lee equipment - it will work.

I enjoy using fine tools for reloading precision loads and feel that they do give me a "edge" in that area. Professional mechanics love Snap-On tools, but in you garage you might do similar work with sockets from harber Freight. But, the first time one of them break and you slam your hand into a manifold, you just might go looking for a better grade tool.

Clovishound

I can appreciate high end tools and machines. If they really do work better, I don't mind spending the extra $.

The other thing is that I am on a tight budget for my reloading. Realistically, I will not be reloading for more than 15 - 20 years. If I have to replace the Lee twice, I'll still be money ahead. From what I read, most agree the Lee are as accurate as anybody's. My buddy's Lee measure has seen many years of use, and is still working well.

The RCBS rockchucker looks like a well made press. I have decided that a turret press will likely fill my needs the best. If I have to buy an RCBS, Lyman, or other high end turret and associated gear, I won't be reloading.

I will definitely stay away from the aluminum casting models. I think those are the ones that most complain about when they talk about Lee junk. Virtually all the reviews/comments I have seen about the Lee caste iron turret press have been very positive.


I still am in a quandary about whether to go with the the die mounted measure, or the bench mounted model. Knowing myself, I will likely just get impatient and go buy the bench mounted model at the LGS.

I did try loading powder through the die on a batch I did the other day. I wasn't really happy with the process. Of course, the likely reason I wasn't happy with it was picking up and putting down the powder and measure, as well as leaving the press in the up position while I loaded powder. If I had the measure, it would dump a load of powder at the top of the stroke. Much simpler. FYI, right now I am only loading 9mm luger. I have no current plans for other calibers, although I did really like the 1911 I shot the other week. Right now, .45 is out of my price range, even with reloading.

Clovishound

Let me ask this question: I do a VMD calc for my powder. I plan on a 4.0 grain load that is the max for the powder/bullet I am using. If the setting I get for my powder measure consistently gives my a 4.1 grain load, I will not be using those loads correct? In the absence of any other discernible error in the process, I will be adjusting to get consistently 4.0 or less load weight off the measure.

Weight is the only way I know of to quality check the accuracy of my loads. I have no way to check pressures. I could get a chronograph and check velocity, but I know of few reloaders who do this. There are also other variables that effect the velocity of a given round.

Bottom line is, I need to be able to quality check my loads. My understanding is that I will do this by weighing my loads.

The VMD calculation, as I understand it, is nothing more than figuring the volume that will give a specific weight based on the density of the powder.

YARDDOG(1)

"[I will definitely stay away from the aluminum casting models. I think those are the ones that most complain about when they talk about Lee junk. Virtually all the reviews/comments I have seen about the Lee caste iron turret press have been very positive.]"

If they are junk. then it's pretty dam good junk I cast for my 9's & 357 mags. using a tumble lube & Junk sizers
Y/D

Darkker

Well, Definitely Maybe.

What the VMD Calc tells you is the grains per CC. So the weight, PER volume.
Not familiar with the auto disk system, just the Perfect Powder measure.

Here is rub. You do the VMD, to get an Association of weight per volume. So once you know the association, which is NOT DEFINITIVE(because of variable BD). You then do your load development in VOLUME, checking the weight at random intervals will only have you chasing ghosts, because the specific bulk density varies.

Example:
VMD calc = .2345
The book START load is 4gr.
4 * .2345 = .938 cc

You need to build loads in Volume(Cc's), OR in Weight(grains). But DON'T randomly interchange.

It is commonly associated that a Bushel of wheat weighs 60#. HOWEVER!
Just like powder, test weight varies. A BUSHEL is a VOLUME, NOT a weight. If you want 60#, you BUY 60# and NOT a BUSHEL.

Clovishound

But the VMD does interchange weight and volume. You start with a weight and then convert it to a corresponding volume using the VMD to calculate this corresponding volume.

If the density of the powder differs within a bottle of powder, then your weights will differ as well. Who is to say whether the powder you did your VMD from is on the high side, or the low side?

If the density if the powder is relatively consistent within this bottle, then there is a direct correlation between the two. This is expressed by the VMD.

If the association of weight and volume is, as you say, not definitive, then why calculate a VMD and use it to calculate a load? How much variation in density is there in a bottle of powder?

Iowegan

Ever see a reloading manual list powder charges by volume? Me either ... always by weight in grains. Don't get strung out on VMD. Get a powder measure with an adjustable baffle or trickle up each charge on a scale.

Darkker

No the VMD does NOT interchange weight, it gives a REFERENCE.
If you read the VMD calc instructions, you start with a VOLUME and THEN tie it to a weight REFERENCE.

"If the density of a powder varies within a bottle of powder, then your weights will vary as well." - When the density varies, the weight is THE ONLY THING that varies. The density of something has nothing to do with its VOLUME. A 1" cube has the same VOLUME whether it is a 1"cube of lead, or a 1" cube of air.

Again, the VMD is ONLY a reference. And that is WHY you DON'T swap back and forth. Do volume, OR weight.

For your question about: what if the BD was heavy when you did the calc.
I already answered that, READ my post below MZ5's....
When the BD is on the high side of the tolerance, THEN the burn rate will be on the slow side of the tolerance.

Meaning:
If it has a high BD, it has a slow BR as well.
Loading by WEIGHT, would have a small amount of slow burning power. The pressures would be much lower than "expected".
Loading by VOLUME would have the same amount as prior to this higher BD powder, HOWEVER because it has a slower burning rate, the pressures will be very close to "expected".




Lowegan,
Yes, in fact I have 2 such books!
As I have said all along, there is no "wrong way". Either is perfectly fine.
But don't go for the "if its so great how come no one does it that way?"
Unless you want to talk about how 99.99999999% of ALL military & COMMERCIAL ammo is loaded by VOLUME.

shootist

Yeah there is nothing finer that the Lyman powder measure on the market, and agree it is snap-on like quality, and Lee is Harbor frieght quality, some people don't understand that cause they never had better

tglazie

The self-righteousness just drips from your Lee-bashing posts. It's quite comical. No matter how many people tell you how effectively the products work for them, or what advantages they offer, or why they dont desire or require a more expensive tool you insist that your tool buying method is the only correct way.

My Craftsman tools have met my needs my whole life and will continue to until I die. If I were a professional mechanic, I might consider Snap-On. Likewise with reloading tools. Some people dont understand that because they are hung up on brand-bashing. But hey, whatever makes you feel good about yourself.

Again, for those who are new to reloading please look beyond the brand-bashing and consider whatever tool is on the market that meets your needs. You will find many many constructive, objective reviews and reviewers on all tools on this site and others.

Clovishound

The definition of density:

The mass density or density of a material is its mass per unit volume.

IOW density is the relationship of weight to volume.

Here is a quote from one of your links from Lee:

"The Volume Measured Density (VMD) of a powder is the volume in cc's (cubic centimeter) that one grain of powder occupies. This can be used to calculate the dipper, disk cavity or powder measure setting required to obtain a desired weight of powder."

According to Lee, the target, or benchmark, is the "desired weight".

They go on to address the same issue I brought up previously:

"If you have a scale check the weight of the powder charge dispensed by the disk combination."

This pretty much settles it for me. I will be using weight as a quality check for the loads my dispenser throws.


Now I just have to decide which dispenser to get.