Fireform Sorting Brass experiment

[culater]

Going to do a controlled experiment of 100 cases of once fired lapua 308.

The theory I'm trying to prove to myself is that I can find the case internal volume consistency just buy loading up my known load.An shoot it with a chronograph to find the consistent cases to shoot tighter ES and SD. Instead of using the water method to find the consistent case internal volume. Which i think maybe flawed because it cant measure case neck tension. Yes you could buy the 21st hydo seater to find the neck tension. But you still have to shoot to find out if its consistent with other brass you just shot.One thing i hope to reduce is the cases that may cause flyers.

Equipment I'm using is my

HS Precision Tactical Take down in 308
Magneto speed chronograph
100 lapua cases 4x firing,and necked turned. I'm going to mark each one 1-100 then record the speed. Then take out the cases with high and low speeds. Then take the new population of cases to load up and test to prove my theory. I should have a very consistent batch of brass to shoot. I should have consistent neck tension on the good brass. I will shooting at 500 yds for the record. I will also load the other brass with the high and low speed and shot side by side at 500yds.

I'll be using my AMP annealer after every firing then size my brass in 2 steps by using Redding neck bushing die then the body die.
Load it up with 44.2 gr +-.002 gn of varget using a 210M primer and the 168 ELD weigh out +-.2 gr.

Tag along if you want just sharing a thought that came to mine awhile ago to try out. I've not heard anyone try this route so that's why I'm doing it.

 

[Sheldon N]

Sounds like a cool test, I'd be curious to see your results.

I helped another shooter out with a similar project a few years ago doing the data analysis. Unfortunately we did not find a correlation between velocity outliers and a specific brass case. Meaning that if a specific piece of brass produced a velocity flier 20-30 fps faster or slower than average, that did not predict whether a velocity flier would happen with that exact same case the next firing around.

Some tips I would suggest so that you get good clean data to work with. Manage barrel cleaning and fouling exactly the same. I'd suggest cleaning the barrel fully, then firing 5 fouling shots, then shoot the cases 1-100 in order. Then for the next test do the same thing again, clean barrel, 5 foulers, then the exact same 100 cases in the exact same order and at the exact same rate of fire and barrel cooling times. Try to test on similar temperature days with calm/favorable shooting conditions and have the ammo be similarly temp controlled. I would not suggest physically pulling the "flier" cases out after the initial 100 firings. Shoot them the second time around and gather the data, then you can do comparative analysis after the fact "pulling" those fliers out in your calculations without having to alter the test procedure.

You mention shooting at 500 yards for record. Are you going to be actually scoring the target as you shoot like an F-Class match? If so, that would be a very useful part of the data analysis. If you have a partner pulling targets and scoring for you, what I would suggest is that they record the elevation deviation high or low for each shot in order. You wouldn't need data on wind or left/right, just whether each shot went high or low. You could cross reference that against velocity and also get a sense of whether a case that threw a physical flier was likely to throw a flier the next time.

Anyhow, good luck with the test. If you want help parsing data in Excel or making charts/graphs I'm glad to assist.

 

[culater]

I figured that 500 yds would be a place to start because you can start see the shots starting to spread out in better detail. I'll be by myself and will be shooting at 24 in steel plate. I'll do 5 shots at a time an do a shot plot on paper and take pic with my phone or tablet. Then paint then shoot ECT ECT

This is a very good read I thought. Very insightful
https://blog.ammolytics.com/2019-02-02/bullet-sorting-part-one.html

 

[Bradu]

Curious to see the results. I'm trying to figure out how far down the rabbit hole I'm going on my long range calibers right now.

 

[culater]

Just try to scratch the OCD problem I have. I'm very close on the decision to buy the 21 th century hydro seater with Wilson die. Can't stand those pesky flyers at long range. You have a few good shot in a 3 to 5 inch water line to 1000 and then one drops out high or low 12 inches. Those are the cases I want to stomp my foot on and into the scrap bin. Ive solved most of my OCD issues with a high end scale and the AMP annealer and better dies. That was a very big increase in lot to lot consistency.

 

[Bradu]

OCD and reloading is a bitch. I've been trying not to let it get to me but it's tough.

 

[culater]

Hi my name is culater and in have OCD reloading reflex dieses and the only know cure at the moment is to keep pulling the reloading press lever on a weekly basis. You know you have it bad if you can convert grains to grams and back grains faster than a crack dealer. Lol ?