Semi educated wild ass guess. SEWAG.johnhefley wrote:Again, Dellet, wow! Thanks.
I'll have to give it a try. I'm using standard Redding dies, so it'll be a little bit more work, but not much.
I just did a quick read on Nosler's website about calculating case fill density. So I have a VAGUE idea what it is.
Did you measure and arrive at your own powder bulk density and case capacity for your calculation?
I've searched high and low for CFE BLK powder bulk density, and can't find it anywhere.
jh
100% density = "0" airspace. That's what you got when you worked the bullet into the powder.
If you looked at the Nosler load data, they are one of the very few that give an actual fill/density rate, instead of compressed or not. It's a very handy thing to know about.
If you look at the 220 grain load with similar charge weights a 10% change in density is close enough to 1 grain, across most of the powders. 1% = .10 grain.
One grain 1680 is 107 fps using 1680, but on all those powders it's probably 70-80 fps as average. For estimating purposes .10 grain=10 fps is close enough for me to estimate.
But look at 1680. 13 grains is 104%. Look in the specs at "case holds". 13.1 grains water with that bullet at that depth. The density of 1680 is very close to water, H110 is a bit closer, you can see the same relationship for the 110 bullet below. I use these powders as a comparison for density. Will a case hold more or less than H110.
The easy way to know more exact density is something like Quickload. It calculates it for you, as long as it has the powder in it's data base
These are just small tricks that help pick powders. One of the reasons I like N120 is that it takes more powder to reach the same velocity as 1680 and it has more bulk. Most powders work better with a higher density. So with a low charge weight I have a better chance at 100% fill with a bulkier powder. That's where CFE missed the mark. It's not very stable at low density loads, High ES, and it is a very high density powder. It takes less weight, that fills less space, to hit a good sub velocity. So unless you have a long bullet you have low density.
Low density, also generally means low pressure and that means lower burn rate and more carbon left behind, runs dirty.
Low pressure loads tend to have higher muzzle/port pressure so they are louder. Some of that can be reduced with an adjustable block.
Just keep working that load and keep twice as many notes as you think you might need. When you can get the ES under control it can be a very accurate powder. It just is frustrating to get there.