Never mind Closed

[Roadrunner1969]

I read somewhere on here about establishing seating depths based on powder fill. Can't seem to find it now.
I am working on a load for 208 ELDM. Hornady load data says 2.25" COAL. I have been able to get SDs down in single digits, but groups are less than desired.
I have tried a few loads using Unique and varying the COAL between 2.2 and 2.35, but haven't found a good load yet. I've seen something about COALs down to 2.1 for this bullet.
Can anyone tell me the process for determining seating depth by powder fill method.
Thanks in advance.

[Roadrunner1969]

Never mind. I found it and it only pertains to A1680 powder.

[dellet]

Was typing during your last reply.

Yes and no, it varies with different powders.

My two favorite example are 1680 and 296/H110 and mostly suppers. But CFE BLk is another good example.

Most powders, work best at a higher load density, the exception is faster pistol powders that were designed for low density charges and are less position sensative. Powder laying along the case bottom when chambered.

Since most manufacturers don’t include load density, you have no idea what it is. Many even seem to forget to warn you a load is compressed. Nosler is the exception to this. It’s worth looking at their data to get an idea.

Programs like quickload will calculate this.

Back to examples.
For all loads I use a fired case, drop the charge, set the bullet on the powder, measure base to ogive or COL. Then depending on powder….
This is for supers

1680, I seat the bullet .010-.015” into the powder.
296/H110 seat the bullet .005-.010” of the powder.
CFE BLK seat the bullet .020” into the powder. Sub or super. If I can’t compress it, I won’t use it.

Accurate #9 I want about 55-60% density. Hard to calculate without a program, and this is one of the many benefits of using one.

I don’t use unique, but what I would do is research some popular loads or those listed as most accurate. Then best I can calculate density for those loads. Generally a pattern emerges. Then start there.

357 magnum loads are a good comparison for bullet weight and pistol powders.

Hope that helps a bit. Mostly you develop your own “system” over time with certain powders.

[Augenblick]

I have unique and h110. The container volume is maybe 40% larger for the unique. They both have about the same density of about 101 lbs/ft^3 but the bulk density for h110 is about 61 lbs/ft^3 while unique is 37 lbs/ft^3. So I need to understand the difference between density and bulk density.

I have only loaded 90 gr xtp on 4.4 gr of unique and 150 gr Hornady fmj with I want to say 5.1 gr of unique both subsonic.

The case fill is on these loads is pretty low with unique.

[dellet]

I have unique and h110. The container volume is maybe 40% larger for the unique. They both have about the same density of about 101 lbs/ft^3 but the bulk density for h110 is about 61 lbs/ft^3 while unique is 37 lbs/ft^3. So I need to understand the difference between density and bulk density.

I have only loaded 90 gr xtp on 4.4 gr of unique and 150 gr Hornady fmj with I want to say 5.1 gr of unique both subsonic.

The case fill is on these loads is pretty low with unique.

Not sure of the exact question, but there will be numbers on the material handling data sheets for the powders, maybe the numbers you listed for H110 and unique. How much a cubic foot of the powder would weigh. From that number you should be able to figure out how much a certain case with a certain volume should hold, if there was no airspace between the kernels of powder.

Or you can simply fill the case with the powder you are using and weigh it.

When I talk about “load density” it is the amount of powder it will take to fill the space in the case left when the bulge is seated at a certain depth.

Nosler has the best data available with out a loading program for load density.

Note that depending on how a case is sized, it will hold 24-5 grains by weight of water. Note in the provided Nosler data, case capacity is much less, that is case volume with the bullet seated at the stated depth.

The next thing to notice is to the right of the load data is the percentage of case fill, loads above 100 percent are compressed loads.



Note the different powders 2400 and H110 at 88%. More than a 10% difference in powder charge weight to get the same case fill ratio.

Current Nosler data.
https://www.nosler.com/300-aac-blackout#BAF49BQ

[Augenblick]

Thanks for that info. I hadn't seen that before.

It wasn't a question so much as I was trying to make a point about the load density of unique powder.

I was out with my wife to see my father in law play music at American legion Post and besides an old couple he invited there was was no one else there but the bar tender. The lady of the couple was showing me pictures of her clothes pin crafts. I quit trying to make my point on the post and just submitted it and went back to looking at clothes pin turkeys.

My pin was that at least in subsonic loads it would be l low density load.