sorting brass by wieght vs capacity vs no sorting

[JFM33]

Really it's been repeatable for me.I will also say I noticed that neck tension
plays a bigger part to consist velocity for me.
John

 

[SheepDog]

Sorting the brass to recorded speed with just one firing could be a mistake. With possible chronograph error and minor interior differences there is no way to be sure that velocity differences are related only to the case. If you could run the same test with all the ammo noting the history of velocities for each case five or ten times you might find that some that would have been side lined are more consistent over time.
Still a statistically representation would likely require 20 to 25 loads fired through each case and at some point you have to draw the line.

 

[mysticplayer]

over the years, I have mucked with case sorting in a wide range of cals and manfs (222 to big boomers). What I gained from all this fussing was:

CASE VOLUME from same brand, same lot rarely varies enough to worry about from case to case in that batch... varying brands and lots can show significant changes in volume but we shouldn't mix our brass so this is moot.

I would fire all cases in the chamber, neck size, trim then compare VOLUME using a super fine ball powder (WCC680 or similar, think salt for grain size). Fill to the brim, tap to compress and ensure completely filled. Dump into the next case, tap down and compare. On a 308 volume case, if the height of the powder varied more then 1mm in height, I would be surprised. Given how dense this powder packs and the little, if any change in powder height in the case, I called it "good enough".

In case someone is going to worry about this change in volume, work out the volume in cc's of 1mm height vs the diameter of a 308 neck... and this would be the WORST variation. In general, there wasn't enough variation to try and measure.

Weight of the case could vary all over the map for some brands and some lots BUT volumes were tight... why I no longer weigh cases.

Obviously, I also did sort by weight (as it was suggested as THE way to go)and found that accuracy could be very poor (mixed lots but same brand)... all the same case weight but after measuring volume, found significant differences.

So, if you want cases to be consistent in volume, measure case volume directly. BUT if you use a modern manf case from the same lot, odds are very good, case volume within that lot will be consistent. Just don't assume same brand - different lot - will have the same case volume.

And as another suggested, I am a firm believer in proper annealing and to maintain consistent neck ductility ... THIS really matters.

YMMV,.

Jerry

PS cases are tested against group size and location of shot vs predicted impact caused by wind. If a shot doesn't make sense, the case is marked and if the case tosses shot again, it is destroyed. Don't toss too many cases these days.

 

[Cburlette]

Here's a test I did using Lapua Palma 308 brass. These were both shot at 600 yards, the larger group was with virgin brass and the smaller group the brass was on its 3rd firing. As you can see the results were inconclusive in that the heavy cases grouped better the first time and the lighter cases did better the second time.

 

[savagedasher]

Ball powder isn't my choice of the way to check volume .
I can take the powder out of the case I have check and return it into the same case with a long drop tube and not have it fill the same .
Happy New Year. Larry

 

[mysticplayer]

Ball powder isn't my choice of the way to check volume .
I can take the powder out of the case I have check and return it into the same case with a long drop tube and not have it fill the same .
Happy New Year. Larry

This super fine stuff you most certainly can repeat the volume... Yeah, I started testing repeatability long before I bothered with the other cases.

You can try salt if you want an analog to compare. Tap the case and it will settle very consistently.

Jerry

 

[mysticplayer]

Interesting, seeing is how I can do the same case 10 times and see at worse .100 grains of extreme spread. With 8 out of 10 giving me no more than .050 grains of extreme spread. If you practice different techniques you will find a very repeatable way. I still measure each 5 times and toss the high and low, then average the three. Try it, it works good and you don't have friggin water in your match brass when you're done lol.

Tom

Yeah, water in my cases took about 3 cases before I gave up on that method

Super fine ball powder, or salt, will work and since I am only concerned with how cases compare relative to each other, I really don't care WHAT the volume is... just that they are the same for that batch of ammo.

Jerry

 

[savagedasher]

This super fine stuff you most certainly can repeat the volume... Yeah, I started testing repeatability long before I bothered with the other cases.

You can try salt if you want an analog to compare. Tap the case and it will settle very consistently.

Jerry

Then your welcome to do it .
Is not something I would depend on .
I don't believe the whole neck can give you the same answer .005 longer neck you end up with a different answer .
My way I check from the shoulder of the brass fired in the same chamber .
Happy New Year Larry

 

[Alex Wheeler]

I know unsorted Lapua brass will shoot 3" 10 shot groups at 1k, and agg well. I am all for doing everything possible to shrink groups. Sorting quality brass is way down the line on importance for me. I think that until you are in the very top level of shooters you will not benefit and even then you may not. If I was to sort brass it would be over a lab radar.

 

[savagedasher]

I know unsorted Lapua brass will shoot 3" 10 shot groups at 1k, and agg well. I am all for doing everything possible to shrink groups. Sorting quality brass is way down the line on importance for me. I think that until you are in the very top level of shooters you will not benefit and even then you may not. If I was to sort brass it would be over a lab radar.

Why not do both even if your not a top shooter.
Happy New Year Larry

 

[dmoran]

Then your welcome to do it .
Is not something I would depend on .
I don't believe the whole neck can give you the same answer .005 longer neck you end up with a different answer .
My way I check from the shoulder of the brass fired in the same chamber .
Happy New Year Larry

Larry -
How do you account for all the variations in case dimensions when volume qualifying with spent brass?
For internal ballistic program input, is the only time I use spent case capacity.

For volume qualification, I want all the cases equalized dimensionally first, and will only qualify the volumes after they have been fired at least twice in the given chamber, sized, trimmed, 100% fully prepped and ready to be loaded. At that point the cases are as equally matched as I can get them to all dimensions. Which is the appropriate time to qualify the volumes (IME), that I myself use ball powder for the task.
Donovan

 

[savagedasher]

Oh yeah, the lab radar also... So I guess I'll do all THREE. Since 3 of the 4 sanctioning bodies/classes have 10 shot records in the TWO'S.

Tom

If you don't try it you could be the first in the ones And totally missed the chances .
Happy New Year Larry

 

[Jet]

Here's a test I did using Lapua Palma 308 brass. These were both shot at 600 yards, the larger group was with virgin brass and the smaller group the brass was on its 3rd firing. As you can see the results were inconclusive in that the heavy cases grouped better the first time and the lighter cases did better the second time.

Thanks for sharing the your test results

Looks like you have better vertical spread on each target with one weight over the other. Might be my eyes since I can't clearly make out all letters.

Good shooting

Rich

 

[Joe Salt]

I'm with Alex on this one, I have been playing with the Lab Radar and with my brass numbered I can keep track of what case does what. And like Donovan said the brass should formed to the chamber, so I'll say this what is the best way then to find volume fired brass or resized brass. I love sticking the stick in the spokes!

Joe Salt

 

[jrb572]

So once formed to the chamber should they get closer in velocity? I can not seem to get my ES below 10. It shots great on paper. But I can never get a single digit ES. I know it's not my scale causing problems and I've tried three different primers. All basically give me the same results. And ES of 10-11. I am checking with a Labradar generally the majority of the shots are within 5 fps of each other. The I get the odd ball 20-30 fps high or low. I am using Varget, win fed cci primers Lapua cases and 185 gr Berger

It's a .308. Average is 2630ish. I will get one or two 2614 and a 2668 in a ten or twenty shot string. So far I have just been using virgin brass.

 

[dmoran]

@jrb572 -
While I have had good accuracy from virgin brass, the velocities are not as consistent and slightly lower then formed cases from the intended chamber. With that said, I suspect the cases being virgins as your culprit. No doubt do to the dimensional variations among the new cases, that in return take small variations in pressure needed to iron them to the chamber walls.
Donovan

(edited my reply)

 

[mysticplayer]

Then your welcome to do it .
Is not something I would depend on .
I don't believe the whole neck can give you the same answer .005 longer neck you end up with a different answer .
My way I check from the shoulder of the brass fired in the same chamber .
Happy New Year Larry

If you reread my first post, you will see that I don't care if the column of powder varies up to 1mm in height in the case neck (fireformed, sized, trimmed cases). Ball park that as 40 thou in column height or what 1 drop of water occupies.

If volume equal to 1 drop of water can affect my loads in a 308 sized case, I sure haven't seen it.

In testing, I try and figure out what type of tolerance I can have for pretty much every part of my reloading process and not see a change on target out to 1000yds. Then I spend more time on the steps that seem to have the most effect and stop worrying about stuff that doesn't matter.

Neck tension, powder weight, seating depth.. these are areas that I spend more time fussing over.

YMMV

Jerry

 

[mysticplayer]

So once formed to the chamber should they get closer in velocity? I can not seem to get my ES below 10. It shots great on paper. But I can never get a single digit ES. I know it's not my scale causing problems and I've tried three different primers. All basically give me the same results. And ES of 10-11. I am checking with a Labradar generally the majority of the shots are within 5 fps of each other. The I get the odd ball 20-30 fps high or low. I am using Varget, win fed cci primers Lapua cases and 185 gr Berger

It's a .308. Average is 2630ish. I will get one or two 2614 and a 2668 in a ten or twenty shot string. So far I have just been using virgin brass.

well you must be doing alot right cause I don't get that type of consistency with virgin brass (although I don't bother to tweak the brass until it has been fireformed). Things will settle down once the cases have been fired 2 to 3 times.

If the groups on paper meet your accuracy needs, I wouldn't waste time worrying about what a chronie might say on its LCD screen.

No one scores the chronie numbers.....

Jerry

PS... confirm with the manf what the error built into your chronie is. Might help you stop worrying about these numbers.

 

[jrb572]

I appreciate the help guys. I get a little anal about things at times. I might try loading some once fired brass and see how my numbers look then.

 

[mysticplayer]

I appreciate the help guys. I get a little anal about things at times. I might try loading some once fired brass and see how my numbers look then.

Worry about things that matter and forget about stuff that doesn't.

A chronie is NOT here I would spend my energies... Understand equipment error and this will become very clear.

Jerry