Identify compressed loads

[asquared19]

Hello everyone. Random question but how do you identify if a load is a compressed load? Is it really clear as you seat? I'm doing some loading for 300wsm and going to try a load with IMR4955 I have on hand as it is somewhat comparable to H4831. It uses more powder the theb H4350 by about 4-5 gr. I'm not trying to achieve compressed loads, just want to know how to identify that I'm running them if applicable.

 

[DiffEQ]

In general, you hear the crunch as you seat the bullet, compacting the top kernels down into the case.

 

[David Christian]

Visually it is pretty easy to see if the kernels are reaching to/past the shoulder/neck junction and where the boat tail of the bullet should be in the case. As stated above, listen for the crunch. Post seating you won’t feel or hear the shake of the kernels.

 

[asquared19]

Visually it is pretty easy to see if the kernels are reaching to/past the shoulder/neck junction and where the boat tail of the bullet should be in the case. As stated above, listen for the crunch. Post seating you won’t feel or hear the shake of the kernels.

Thanks for the added suggestion of listening for the shake after. This is helpful. Likely it won't be an issue with the load but I just needed to know what to look for.

 

[J_idaho]

Shake shake

 

[Rocketvapor]

98% fill or above and you probably won't hear or feel the shake.
Take a case with as fired neck, add your charge.
Drop a bullet in. Measure length.

Different 'FILL' with funnel or drop tube.

 

[RegionRat]

Whenever I run a new recipe, I have to run a test of the seating depth versus the powder fill.
As mentioned above, I take a representative case that is new virgin brass that is heavy for the batch, and one that has been fired but unsized. These would represent the two extremes of case volume.

I take my mandrels and find the one that will expand the necks to the point where a bullet can just barely slide. I install a spent primer in the pocket, upside down in order to plug the hole.

I then measure internal capacity in water grains. In the samples below, the virgin case is 31.52 grains of water, and the fired-unsized case is 32.44 grains of water.

I know the bullet geometry and roughly where I will stop taking data is when the bullet would get slightly into jam. I also note to myself where magazine length would be as well as when the boat tail is at the neck-shoulder junction.

I get to work dispensing powder then shaking and tapping to settle the bullet onto the powder column and I take a COAL reading.

Sometimes, you may want to lift the bullet slightly and re-settle to get several readings before you plot the point. There is some dispersion in each attempt, but it works out when you get methodical about how you do this.

In the plots, you can see inflection points when the powder starts to climb the shoulder and the boat tail gets up into the neck. Having done this drill now for many decades, I have seen the pattern dozens of times.

Here is an example of Norma 204 Ruger brass, with VV N-140 and a Hornady 40 VMax. Each point represents the COAL when the bullet is slightly compressing the powder charge.



It takes a little time, but without any other place to get the information, I have no choice but to run the test. Once I know when the bullet hits the powder column and starts to compress the load, I know what to expect in the ladder tests and when I select a seating depth. YMMV

 

[6BRA]

Most powders through a drop tube and or some form of vibration, will go from compressed to not being compressed. An 1/8th of an inch difference visually. If you are playing on quickloads the above will let you run at 107 to 108 percent case fill.

 

[asquared19]

Thank you all for the info.

 

[jepp2]

Random question but how do you identify if a load is a compressed load?

Many great suggestions, most are pretty late in the loading process. The Nosler load data lists case fill for each load listed. Quickload and GRT also show case fill and % burned, very helpful.

 

[6Creed73]

I measure with a compressed load test case. I use a bushing die with the bushing removed to size the body, but not the neck so a bullet will drop in. I then seat a spent primer, drop my charge, and insert a bullet to where it touches the powder.

Then I take a CBTO measurement which becomes my baseline. After seating a bullet to my desired depth in a charged case, I can now compare measurements.

So let's say the test case with bullet just touching powder is 1.520 and my live cartridge measures 1.510...I know that I'm .010 compressed.

 

[J_idaho]

98% fill or above and you probably won't hear or feel the shake.
Take a case with as fired neck, add your charge.
Drop a bullet in. Measure length.

Different 'FILL' with funnel or drop tube.

Ya but you have from the shake point to the cant seat crunch point. It’s pretty easy to take measurements of where not to fill too when you can’t reach your desired seating depth.

 

[762willdo]

Snap crackle and pop……..

 

[jelenko]

My rather quick and dirty test.

Seat an empty case with a bullet to my desired seating depth/COAL.
Load powder into a prepped case; seat with the same setting as above. Measure COAL. If it's longer by more than a couple thousandths, it means the powder is pushing back.

 

[6Creed73]

My rather quick and dirty test.

Seat an empty case with a bullet to my desired seating depth/COAL.
Load powder into a prepped case; seat with the same setting as above. Measure COAL. If it's longer by more than a couple thousandths, it means the powder is pushing back.

If the powder is pushing the bullet out, it's quite a bit compressed. In my opinion, knowing the load is compressed is less important than knowing how much it's compressed. A compressed load isn't a big deal, I run compressed as much as I can, depending on powder. But you don't want it compressed to the point the bullet starts to deform, or it messes with you seating depth by pushing the bullet out a few hours later.

If you try the measuring method I mentioned above, it will allow you to track load performance in relation to how much it's compressed. In my experience, touching powder vs compressed .015 can change your load quite a bit. One of my loads loves to be about .005 compressed, and the only way I can know that is to keep track of that measurement when I'm developing a load.

 

[asquared19]

Many great suggestions, most are pretty late in the loading process. The Nosler load data lists case fill for each load listed. Quickload and GRT also show case fill and % burned, very helpful.

View attachment 1526574

Thanks for pointing that out.

 

[Dave M.]

Many great suggestions, most are pretty late in the loading process. The Nosler load data lists case fill for each load listed. Quickload and GRT also show case fill and % burned, very helpful.

View attachment 1526574

Is this out of a manual? From a website? Or from GRT? QL?
Dave

 

[Fast14riot]

If you're using H4831 and not H4831sc, use a drop tube and or tap the case to settle the powder. Its pretty big kernels that will fill the case. Some people use an electric toothbrush to vibrate the case and get powder to settle.