Neck turners/precision reloading

Lead hammer said:
So the point is that the hardness of the brass before annealing is relative to the hardness after annealing.

I'm not sure I understand that reasoning. Could you elaborate some?
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When brass is heated to a certain temperature it softens at a certain rate. Raise it to a higher temperature and is softens at an even faster rate.

So annealing brass occurs as a result of a fixed recipe consisting of a certain target temperature for a certain amount of time.

That time and temperature combination does not know how hard or soft the brass is when you perform it.

If the brass 'A' is already soft, it will get even softer.

If brass 'B' is hard, it will get softer, but not as soft as 'A'.

The brass does not know how soft you want it to get. It only gets softer relative to how hard or soft it was before you anneal in reaction to the time at temperature.

The best way I know of to determine brass hardness is to start with neck turned brass and use a Redding style neck sizing bushing. Keep track of what size bushing is needed to acquire adequate neck tension, or a target ID as measured from a pin gage.

The harder the brass gets, the more spring back you will get.

So suppose you are sizing neck turned brass for a 308 and you want .306 after neck sizing with a certain bushing. You pin gage the brass and find some are .305 and some are .307... Well the ones that are .305 are softer, and the ones at .307 are harder.

Now you can sort into hardness lots as a result of pin gaging the ID.
 
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Not exactly... when cartridge brass get to the annealing temperature , it does not matter how hard or soft they started. They will be all the same and uniform, if exposed at the same temperature for the same amount of time.

If you see variation such as .305 - .307 with the same bushing, your neck are not uniform or your brass was not annealed properly ( or measuring tools are not up to the task )

Some anneal after neck turning, some before. Properly done, all the neck will be exactly the same after sizing. Myself, I size with a bushing die with no expander and use a mandrel to get an extra measure of uniformity in neck tension. For hunting ammo, it does not matter, but shooting bugholes, it does.

Keep in mind that turning neck for a standard chamber that might already be on the large side of SAMI specs in the neck area, can lead to neck split because of an overlay large tolerance created by doing so.

Uniforming yes, too much no. No amount of annealing will save your brass if you turn your neck too thin and create to much ‘free play ‘ between the loaded round neck dimensions and the chamber neck dimensions.
 
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Janeau said:
Not exactly... when cartridge brass get to the annealing temperature , it does not matter how hard or soft they started. They will be all the same and uniform, if exposed at the same temperature for the same amount of time.

If you see variation such as .305 - .307 with the same bushing, your neck are not uniform or your brass was not annealed properly ( or measuring tools are not up to the task )
Some anneal after neck turning, some before. Properly done, all the neck will be exactly the same after sizing. Myself, I size with a bushing die with no expander and use a mandrel to get an extra measure of uniformity in neck tension. For hunting ammo, it does not matter, but shooting bugholes, it does.
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This makes more sense to me. I don't think the metal "remembers" what it's previous hardness was.

But it's been a long time since I've taken a class in metallurgy, so I could be mistaken.
 
Brass will have a temp/dwell time link, 500 degrees to temper would take a long time, 750 degrees is seconds. As long as the brass reaches 750 thats our goal. If your brass is from the same amount of cycles they should always be close to each other, thats why I like the idea of annealing after every firing. I would think the temperature of the brass could alter dwell time but brass temp changes so quickly anyway, especially at the higher temps.
 
So let's think about this from a different perspective and maybe it will get more clear... Let's exaggerate the point for clarity.

Take a piece of brass and anneal it, then do it again 3 more times... or how about 10 more...

Do you actually think after the last annealing that it will be the same hardness as it was after the first annealing?

That's like saying it does not matter how long you anneal for.

If after the last annealing the brass is actually the same hardness as it was after the first... then that pops the AMP anneal bubble and blows it to pieces. In which case it is just an expensive way to do exactly what salt bath does.

We cant suck and blow at the same time here.

As for neck turning in my example above, I'm referring to a control group. I don't want to cloud the conversation and turn it into a debate about if you should or should not neck turn.

Janeau is not correct in the assumption that something else is wrong if there is a post resize variation. Inside neck size variation on neck turned brass is exactly proportional to hardness.

I run tight neck chambers in competition guns and neck turn all my competition brass, and have been for 20 years. I have beaten this path to death over that time and have validated and re-validated over the years.

Suggesting that there is something "wrong" is a point that is blind to the point. There is variability in the annealing process itself... don't look to some other thing to throw the blame off what you don't want blamed. Think about cognitive bias.

The brass does not have a natural hardness level that it magically wants to be. It does not gravitate to the hardness you want it to be. It just reacts to heat over time.

As for annealing after every firing... That does not necessarily make things more consistent. If you're annealing brass that is still soft, it's just getting progressively softer after every cycle.... not necessarily more even.
 
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Maple57 said:
So let's think about this from a different perspective and maybe it will get more clear... Let's exaggerate the point for clarity.

Take a piece of brass and anneal it, then do it again 3 more times... or how about 10 more...

Do you actually think after the last annealing that it will be the same hardness as it was after the first annealing?

That's like saying it does not matter how long you anneal for.

If after the last annealing the brass is actually the same hardness as it was after the first... then that pops the AMP anneal bubble and blows it to pieces. In which case it is just an expensive way to do exactly what salt bath does.

We cant suck and blow at the same time here.

As for neck turning in my example above, I'm referring to a control group. I don't want to cloud the conversation and turn it into a debate about if you should or should not neck turn.

Janeau is not correct in the assumption that something else is wrong if there is a post resize variation. Inside neck size variation on neck turned brass is exactly proportional to hardness.

I run tight neck chambers in competition guns and neck turn all my competition brass, and have been for 20 years. I have beaten this path to death over that time and have validated and re-validated over the years.

Suggesting that there is something "wrong" is a point that is blind to the point. There is variability in the annealing process itself... don't look to some other thing to throw the blame off what you don't want blamed. Think about cognitive bias.

The brass does not have a natural hardness level that it magically wants to be. It does not gravitate to the hardness you want it to be. It just reacts to heat over time.

As for annealing after every firing... That does not necessarily make things more consistent. If you're annealing brass that is still soft, it's just getting progressively softer after every cycle.... not necessarily more even.
Click to expand...

So, this is coming from a metallurgical engineer...

All heat treatment processes rely on equilibrium (phase) diagrams (or it should if to be done properly). Equilibrium diagrams typically show the different phases of two alloys and is a function of the concentration of elements and temperature.

Take a look at this graph;
main-qimg-b498c0f2603385c64b7669b28788b9c3-c


For a given alloy, if you can consistently take it above the crystallization area in the phase diagram and keep there long enough to permit recrystallization to occur, then you'll have the same residual hardness all the time, no matter how many times brass is shot with or without annealing in between...

So, different brands, or even the same brand but different lot/batch, of cases may have different residual hardness after annealing if they do not have similar chemistry. For that reason, I think it is very important NOT to mix brasses purchased separately (unless you are buying high-quality brass where manufacturer have quality control processes in place keeping very consistent alloy chemistry).
 
aakoksal, I would be very interested in formally testing to confirm this effect on brass using the type of annealing tools hand loaders use... not some highly controlled heat treat facility.

How we define properly is the key.
 
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Maple57 said:
aakoksal, I would be very interested in formally testing to confirm this effect on brass using the type of annealing tools hand loaders use... not some highly controlled heat treat facility.

How we define properly is the key.
Click to expand...

If you ask my opinion, salt bath would give the most consistent result if the temperature control system is accurate enough...
 
aakoksal said:
So, this is coming from a metallurgical engineer...

All heat treatment processes rely on equilibrium (phase) diagrams (or it should if to be done properly). Equilibrium diagrams typically show the different phases of two alloys and is a function of the concentration of elements and temperature.

Take a look at this graph;
main-qimg-b498c0f2603385c64b7669b28788b9c3-c


For a given alloy, if you can consistently take it above the crystallization area in the phase diagram and keep there long enough to permit recrystallization to occur, then you'll have the same residual hardness all the time, no matter how many times brass is shot with or without annealing in between...

So, different brands, or even the same brand but different lot/batch, of cases may have different residual hardness after annealing if they do not have similar chemistry. For that reason, I think it is very important NOT to mix brasses purchased separately (unless you are buying high-quality brass where manufacturer have quality control processes in place keeping very consistent alloy chemistry).
Click to expand...


Thank you for posting. It has been some time since I looked at one of those.

Regards
Ronr
 
Maple57 said:
So let's think about this from a different perspective and maybe it will get more clear... Let's exaggerate the point for clarity.

Take a piece of brass and anneal it, then do it again 3 more times... or how about 10 more...

Do you actually think after the last annealing that it will be the same hardness as it was after the first annealing?

That's like saying it does not matter how long you anneal for.

If after the last annealing the brass is actually the same hardness as it was after the first... then that pops the AMP anneal bubble and blows it to pieces. In which case it is just an expensive way to do exactly what salt bath does.

We cant suck and blow at the same time here.

As for neck turning in my example above, I'm referring to a control group. I don't want to cloud the conversation and turn it into a debate about if you should or should not neck turn.

Janeau is not correct in the assumption that something else is wrong if there is a post resize variation. Inside neck size variation on neck turned brass is exactly proportional to hardness.

I run tight neck chambers in competition guns and neck turn all my competition brass, and have been for 20 years. I have beaten this path to death over that time and have validated and re-validated over the years.

Suggesting that there is something "wrong" is a point that is blind to the point. There is variability in the annealing process itself... don't look to some other thing to throw the blame off what you don't want blamed. Think about cognitive bias.

The brass does not have a natural hardness level that it magically wants to be. It does not gravitate to the hardness you want it to be. It just reacts to heat over time.

As for annealing after every firing... That does not necessarily make things more consistent. If you're annealing brass that is still soft, it's just getting progressively softer after every cycle.... not necessarily more even.
Click to expand...

I get what you are saying but struggle with the idea still. So most people anneal at 750. So how long does the dwell time at 750 need to be. If most set their annealer for 4-5 seconds ( pick 5 ) we are looking at what, one tenth of a second off the target time when taking in account time variables in the process? So what would the difference in the final hardness be between a dwell of say 5 seconds when at 750 degrees give or take 1/10th? The best way would be to measure seating force for each round and place them in groups accordingly.
Annealing example.
same heat, distance to the flame, time 5 seconds. Brass is once fired. dwell time 4.95, 5.0, 5.0 ,5.1 ,4.9, 4.95. 2nd firing the same brass in exact same order is 5.0, 5.1 ,4.95, 4.9, 5.0, 4.95. Is the average brass hardness getting closer together, farther apart, or the same? I thought brass annealing temp when getting hotter, that the curve is not linear, so the dwell time would be much less critical at 1/10th of a sec near 750, than 1/10th of a sec at 500 degrees. I need to find the chart I had seen at one point.
 
I would agree that seating force is the ultimate separator. Even more so than pin gaging the ID.

The reason I would say seating force is more relevant is that soft brass with dimensionally smaller ID may have less seating force than harder brass with a larger ID.

However those variables shake out would be reflected in seating force.

I don't have a seating force gage myself, but a good buddy does who was on the Canadian F Class team until only recently, and he swears by it for crazy low velocity spreads. He told me just this past Friday that he was getting something around 1/4" of vertical at 900 meters during practice at Connaught in Ottawa. Keep in mind that was during a team load testing session under light conditions early in the day while the sun was low.

He also may have been exaggerating just a bit, but only in the sense that it's hard to see 1/4" from the firing point at such a distance. It may have looked like 1/4" to him from the firing point, but the guy in the butts may have had a slightly different story. I would still believe it would not have exceeded 1/2". I don't know if they actually went to the butts and looked at the target.

I also agree the annealing rate changes with temperature as you stated. A chefs knife can get annealed in the dishwasher. That's why they say only to hand wash a good knife. Repeated exposure to relatively low temperature is enough to soften steel after enough cycles. A dishwasher is far from red hot.
 
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I think the dishwasher heats to well less than 200 F. Most steels temper at like 350-400 F for like 2 hours. I think the detergent has a lot to do with the edge damage in the dishwasher as well. My good hunting and pocket knives never get the bad treatment.
 
Maple57 said:
I would agree that seating force is the ultimate separator. Even more so than pin gaging the ID.

The reason I would say seating force is more relevant is that soft brass with dimensionally smaller ID may have less seating force than harder brass with a larger ID.

However those variables shake out would be reflected in seating force.

I don't have a seating force gage myself, but a good buddy does who was on the Canadian F Class team until only recently, and he swears by it for crazy low velocity spreads. He told me just this past Friday that he was getting something around 1/4" of vertical at 900 meters during practice at Connaught in Ottawa. Keep in mind that was during a team load testing session under light conditions early in the day while the sun was low.

He also may have been exaggerating just a bit, but only in the sense that it's hard to see 1/4" from the firing point at such a distance. It may have looked like 1/4" to him from the firing point, but the guy in the butts may have had a slightly different story. I would still believe it would not have exceeded 1/2". I don't know if they actually went to the butts and looked at the target.

I also agree the annealing rate changes with temperature as you stated. A chefs knife can get annealed in the dishwasher. That's why they say only to hand wash a good knife. Repeated exposure to relatively low temperature is enough to soften steel after enough cycles. A dishwasher is far from red hot.
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A common practice among the wet tumbling crowd is to dry their brass in the oven at 170 F for 20-30 minutes. In your opinion, would multiple cycles of drying in the oven like this eventually soften the the brass a measurable amount? I know I can get 30 reloads out of a 45 acp case, if I dried them in the oven for half an hour every reload, that would work out to 15 hours total at 170 F by the 30th cycle.
 
coyoteking said:
A common practice among the wet tumbling crowd is to dry their brass in the oven at 170 F for 20-30 minutes. In your opinion, would multiple cycles of drying in the oven like this eventually soften the the brass a measurable amount? I know I can get 30 reloads out of a 45 acp case, if I dried them in the oven for half an hour every reload, that would work out to 15 hours total at 170 F by the 30th cycle.
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I don't know what minimum temperature begins to have an effect, but I do know that an oven can certainly get hot enough to have an effect on the hardness of brass.

We have no way of knowing what temperature everyone uses to dry brass. Likely some use a higher temperature without considering the points made here.

I don't think 170 degrees F would present a problem though.
 
Interesting comparison here between annealed and not annealed.

It would be nice to know more about how these rounds were selected and how the necks were resized.

Not to assume the worst, but it is possible that cases were selected for each group based upon neck wall thickness variations to rig the test results... hopefully that's not the case.

 
As far as the neck turning part of it goes, I think that 21st Century has taken the right approach in their offerings. Their cutters are available with the proper shoulder angles, and the 3 way trimmer is available as well, they have various sizes of turning mandrels and expanders and inside reamers to suit. As they say, their mandrels fit Sinclair tools as they used to make them for them, also happen to work in a Lyman M die. My only beef is that it sure adds up with different cartridges. But that's the way of it with exotic tooling. You want to play with shooting bugholes, you have to work with with minutiae, be prepared to pay for it. I guess that is why we are called Gun Nuts.
 
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