Soft 6br Norma brass

[Pareto]

I know that the 6mm BR brass from Norma has a reputation for being soft. But I was surprised that about 20 of my cases shot 3x to 4x each were so soft after annealing and full length resizing that there was only minimal neck tension. In all cases, the slightest push would lead to the bullets going deeper into the case. So depth adjustments are pointless. Do I have no option but to trash this brass? Or is there a simple way to save them for a couple more uses?

Thanks.

 

[gunsandgunsmithing]

Why not drop down a bit with bushing size? Generally, spring back happens most due to brass being too hard vs too soft. It just springs back after sizing rather than holding desired neck "tension"

 

[mgunderson]

Norma typically needs a smaller bushing for me. Some of the neck thicknesses change for lots between norma and lapua. Check the od of a loaded round and you will likely see the norma is smaller. That isn't always the case. Please check yours and let us know.

 

[Pareto]

But with the 80 or so other pieces of Norma I have there is no issue using the 0.267 neck bushing and the tension seems similar to the Lapua brass. But with these 20 pieces there is virtually zero neck tension.

I wonder if I had over annealed this brass by mistake.

 

[rwj]

But with the 80 or so other pieces of Norma I have there is no issue using the 0.267 neck bushing and the tension seems similar to the Lapua brass. But with these 20 pieces there is virtually zero neck tension.

I wonder if I had over annealed this brass by mistake.

How much variation is there in neck wall thickness between the cases in the lot?

 

[Straightshooter1]

But with the 80 or so other pieces of Norma I have there is no issue using the 0.267 neck bushing and the tension seems similar to the Lapua brass. But with these 20 pieces there is virtually zero neck tension.

I wonder if I had over annealed this brass by mistake.

How thick are the necks for the 20 pieces vs for the other 80?

 

[Pareto]

Not using a micrometer, I compared a few random pieces with a few from the good pile. They're all in the range of 0.269 to 0.270. Maybe an odd 0.268 if I'm mismeasuring.

 

[Straightshooter1]

Not using a micrometer, I compared a few random pieces with a few from the good pile. They're all in the range of 0.269 to 0.270. Maybe an odd 0.268 if I'm mismeasuring.

That really doesn't tell us anything about neck wall thickness.

 

[Pareto]

Sorry. It seems to be 0.012 vs 0.014

 

[JFrank]

I know that the 6mm BR brass from Norma has a reputation for being soft. But I was surprised that about 20 of my cases shot 3x to 4x each were so soft after annealing and full length resizing that there was only minimal neck tension. In all cases, the slightest push would lead to the bullets going deeper into the case. So depth adjustments are pointless. Do I have no option but to trash this brass? Or is there a simple way to save them for a couple more uses?

Thanks.

Maybe you should stop annealing these cases.

 

[Pareto]

Maybe you should stop annealing these cases.

So just keep resizing them till they're hardened?

 

[JFrank]

So just keep resizing them till they're hardened?

Correct

 

[rwj]

Sorry. It seems to be 0.012 vs 0.014

Was neck thickness measured using a ball micrometer?

Using the measurements provided, the neck ID of your sized cases will range between .240/.246” To ensure an interference fit for the bullet (.243 nominal OD), you’re going to need a smaller ID neck. Either use a smaller neck bushing or smaller expander mandrel/ball.

 

[Webster]

I know that the 6mm BR brass from Norma has a reputation for being soft. But I was surprised that about 20 of my cases shot 3x to 4x each were so soft after annealing and full length resizing that there was only minimal neck tension. In all cases, the slightest push would lead to the bullets going deeper into the case. So depth adjustments are pointless. Do I have no option but to trash this brass? Or is there a simple way to save them for a couple more uses?

Thanks.

Neck tension can be adjusted. I would bet money the necks are not to soft. How are you annealing. If your using a FL die you are stuck with the tension the die provides. Get a redding FL S bushing die. Or a bushing die from Harrels or Whidden. I turn my 6BR necks to 0.0125" and use a .265 bushing. It's really pretty hard to over anneal necks if you don't heat to red for more than a few seconds. Time at temp is just as important as what the temp is.

 

[NorCalMikie]

Maybe you should stop annealing these cases.

BINGO!! My first thought!! When you don't get as much SPRINGBACK, "then" think about annealing. Don't make more work for yourself that you need.

 

[JFrank]

The best use for a propane torch is lighting my wood stove in the morning. No newspaper required, just place kindling like a Tee Pee and anneal for 20 seconds.
Happy Thanksgiving Y’all
Jim

 

[Pareto]

Neck tension can be adjusted. I would bet money the necks are not to soft. How are you annealing. If your using a FL die you are stuck with the tension the die provides. Get a redding FL S bushing die. Or a bushing die from Harrels or Whidden. I turn my 6BR necks to 0.0125" and use a .265 bushing.

I have a Redding FL bushing die and also a Wilson one. I have bushing from 0.264 to 0.267. I'll try the 0.265 instead. The measurement for the neck thickness I previosuly indicated was between 0.012 and 0.014 with a ball micrometer combined with the outward neck width, would mean that 0.269 or 0.270 minus 0.021 or 0.026 would give me an inner diameter in the general range of 0.240/0.247

 

[searcher]

Correct

As Jfrank says, resizing them induces work-hardening. If you use smaller neck bushing to where it will hold a bullet well enough for you, just one firing of the cases will make the necks harder as well. Sounds like you are just getting those cases a bit too hot when annealing. Those cases can likely be salvaged without issues. I've gotten cases hot enough to distort the necks - and that is crossing the line on being able to save them. Anything less and those cases will come back from being too soft by resizing and firing them.

 

[Webster]

I have a Redding FL bushing die and also a Wilson one. I have bushing from 0.264 to 0.267. I'll try the 0.265 instead. The measurement for the neck thickness I previosuly indicated was between 0.012 and 0.014 with a ball micrometer combined with the outward neck width, would mean that 0.269 or 0.270 minus 0.021 or 0.026 would give me an inner diameter in the general range of 0.240/0.247

Simplify the math. Measure the case o.d. before and after seating the bullet. Remember that what we call holding tension is not really the grip on the bullet. It's a diameter change. The 0.002' is what the best shooters recommend maybe go to 0.003" in some cases.

 

[Murray Brook]

@JFrank
Great idea for the propane cylinder. Have to remember that.