Brass Length

[H3nchman]

I have a lot of mixed LC 556 brass I have been using for load development. After sizing some brass measures to 1.745" and others measure to 1.754" which my Lee trimmer cuts consistently too.

1. If I use the brass mixed lengths, how will that affect my load development? will poi change?

2. If I use the 1.745" brass, once it eventually grows, will the load I develop change once the brass is trimmed to 1.754"?

I tried googling and did not find a definitive answer.
Thanks,
-Matt

[robert101]

If you are shooting to say MOA and wider it won't matter much at all. If you are a bench rest competition shooter I venture it would. Since you are asking this question, I'm guessing your needs are less than the most optimal. I will typically shoot mixed brass and vary length sizes and still get MOA with inexpensive target bullets. That is good enough for my target needs. Of course your standards may vary.

[eric n]

Test it and you will know for sure.
(It's near the bottom of the list of things that matter)

[CSACANNONEER]

Mixed cases equals different case capacities. Mixed OAL equals different neck tensions. So, you're not going to get the utmost consistency out of your loads until you eliminate both of those variables and, possibly more.

[H3nchman]

Mixed cases equals different case capacities. Mixed OAL equals different neck tensions. So, you're not going to get the utmost consistency out of your loads until you eliminate both of those variables and, possibly more.

That's what I was thinking. If the brass grows to 1.754" how much will the load change? Obviously neck tension will be different, but will 0.009" of brass length matter?

[CSACANNONEER]

That's what I was thinking. If the brass grows to 1.754" how much will the load change? Obviously neck tension will be different, but will 0.009" of brass length matter?

It will matter. How much it will matter is something that only you can find out through testing. Will it matter to you? Will you even be able to measure the difference? That will depend on your barrel and your proficiency.

[Dnele928]

If you load some of each, then do some target work, can you post the results? This would be good to know.

[diveRN]

^^^ It has pretty much been said.

What is your end-goal for your work up?

On one end of the spectrum, consistent cases matter a lot if you're working up match rounds to shoot from a rest. You'll want to eliminate as many variables as you possibly can. On the other end, if you're just working up a dependable, medium-charge target/plinker round ... it matters much, much less.

I use a case gauge for .223 target rounds, I don't use a caliper and they get loaded on a 650. These are plenty accurate for me shooting paper and 6" plates at 100 yards with a 1x4 scope. My process becomes much, much more meticulous when I'm loading hunting rounds in all calibers.

[bazineta]

So long as the necks are within the SAMMI limits and thus safe, the only thing that's a big deal with varying lengths is that a consistent crimp becomes challenging to apply. As CSA has indicated already, you've got much larger variables anyway.

[H3nchman]

My end goal is to work a load that will shoot at lease 1/2 MOA. I know the rifle is capable of it. I have shot that with factory ammunition (freedom munitions 77 gn reman that is loaded with mixed LC brass). I have since sorted the lot, pulled out a specific year, culled for of center flash holes and any case defects, and made sure all are close in length +- 0.002".

[eric n]

Your mixed brass will have a bigger result then .010 diff in necks.
If you are talking purely neck tension...
What lube you have in your necks matter. Mica, graphite, carbon, carbon/walnut residual, whatever. Squeaky clean isn't good(for me).
What bushing, expander, or button you use matters.
Turning? Depends
Freebore and seating past the neck shoulder junction matters if you get donuts.
Shooting a tuned return to battery gun you will see the difference.
Let the short ones grow and trim them all when they get 1.754.
1/2 Moa is easily attainable with powder and seating tune if you and the gun are.
Damn... almost forgot annealing. (Not going there)
If you want to know for sure, shoot your long ones against your short ones.
What bullet are you shooting?

[OpenSightsOnly]

My end goal is to work a load that will shoot at lease 1/2 MOA. I know the rifle is capable of it. I have shot that with factory ammunition (freedom munitions 77 gn reman that is loaded with mixed LC brass). I have since sorted the lot, pulled out a specific year, culled for of center flash holes and any case defects, and made sure all are close in length +- 0.002".

Some folks trim to 1.745" so that saves them from trimming after every FL sizing or some have used the RCBS Xdie to achieve the same effect.

My Giraud trimmer is set to trim 223 brass at 1.752" and I load 77s and 80s. Haven't had any safety or performance issues.

[H3nchman]

Your mixed brass will have a bigger result then .010 diff in necks.
If you are talking purely neck tension...
What lube you have in your necks matter. Mica, graphite, carbon, carbon/walnut residual, whatever. Squeaky clean isn't good(for me).
What bushing, expander, or button you use matters.
Turning? Depends
Freebore and seating past the neck shoulder junction matters if you get donuts.
Shooting a tuned return to battery gun you will see the difference.
Let the short ones grow and trim them all when they get 1.754.
1/2 Moa is easily attainable with powder and seating tune if you and the gun are.
Damn... almost forgot annealing. (Not going there)
If you want to know for sure, shoot your long ones against your short ones.
What bullet are you shooting?

What do you mean donuts?
-I am using rcbs lube that came withy kit. Brass gets walnut tumbled, decapped and FL sized, crimps removed, primer pockets cleaned, and a chamfer and deburr. I am shooting Hornady 75 hpbt. May come side annealing just the brass for this gun 100-200 should not take too long.

-I am having trouble finding one lot of brass. I have a lot of wolf gold (223 but rumored to be 556 cases? ) Zqi brass marked Ik 13. Lake city heavily mixed and FC 556, and cbc 556. What is my best choice for consistency?

[OpenSightsOnly]

What do you mean donuts?
-I am using rcbs lube that came withy kit. Brass gets walnut tumbled, decapped and FL sized, crimps removed, primer pockets cleaned, and a chamfer and deburr. I am shooting Hornady 75 hpbt. May come side annealing just the brass for this gun 100-200 should not take too long.

-I am having trouble finding one lot of brass. I have a lot of wolf gold (223 but rumored to be 556 cases? ) Zqi brass marked Ik 13. Lake city heavily mixed and FC 556, and cbc 556. What is my best choice for consistency?

Hornady's 75 HPBT is very good, and I use the 75s and 77s for my reloads. I use once fired LCs or WCCs and sort them based on year, easier to swage with the Dillon 600.

For a brass fired from a gas gun, don't bother with annealing since you may have to toss the brass around the 6th or 7th firing due to primer pockets loosening-up or cracks on the case neck.

[eric n]

What do you mean donuts?
-I am using rcbs lube that came withy kit. Brass gets walnut tumbled, decapped and FL sized, crimps removed, primer pockets cleaned, and a chamfer and deburr. I am shooting Hornady 75 hpbt. May come side annealing just the brass for this gun 100-200 should not take too long.

-I am having trouble finding one lot of brass. I have a lot of wolf gold (223 but rumored to be 556 cases? ) Zqi brass marked Ik 13. Lake city heavily mixed and FC 556, and cbc 556. What is my best choice for consistency?

Donuts are a build up of brass at the neck shoulder junction. When you are seating a bullet and the flat base or boattail/heel transition goes by the neck/shoulder junction if you feel a pop, you have a donut. Or drop a bullet into a fired case and if it doesn't drop into the case, you have a donut. They destroy your accuracy unless you seat the bullet in front of them. I'm assuming you are using an AR so don't worry about it, you have to seat it deep with 75g and mags.
I would sort as best you can by headstamp and year.
I use the carbon in the necks along with residual media dust left over from tumbling for neck lube as well.