Brass springback over time

[Webster]

To bolt drop test the 4 Lots of sized cases, 08-09-14-15, I removed the firing pin from the bolt to do a test on 3 cases from each lot. The bolt dropped as if I had just sized the brass cases on each lot.

I don't know if you test bolt drop on your freshly sized case or not but I would recommend it, then in a period of time do another bolt drop test and check the cases for different result.

That was a good question you asked, made me wonder. After my testing I'm not going to worry about spring back in my cases. I have no theory about why my bump changed by 0.002 plus thousands but my initial bolt drop test stayed the same. My process works well far as I'm concerned, proper annealing and 10 second dwell time of the case in the sizing die.

Load them up and go to your shoot and have fun and don't worry about your loads. Worry about
pulling the trigger properly. Good luck!

Like someone said a tiny change in the wind will do more to move a bullet out of a group than any OCD measurements you do in your basement.

 

[Timon]

After firing, I first pop out the primers, then anneal before anything else. Then the brass gets sized. Shortly after sizing I have found that I get right about 1/2 thousandths of springback, using gage pins. I then use a mandrel on the cases and I find very little springback on the cases following the mandrel use. Not enough that I can really measure it. In my opinion, you get about 1/2 thousandths of springback follow sizing and that is pretty much it. Unless the brass is subjected to some type is large temperature change. In that case, I believe the case neck diameter might change, but it’s not a function of a springback, it’s just a temperature shift.

 

[Oldbloke]

Does the shoulder get hot enough when annealing?
May have been mentioned.

 

[Timon]

You do not want the shoulder to heat up too much, as it should remain hard to prevent the bullet and neck from collapsing during seating.

 

[Oldbloke]

I think it's pretty difficult to do that.

 

[JFrank]

I think it's pretty difficult to do that.

After watching the video, I don’t see much sizing difference between annealing or not annealing. His seating pressure had some variations, I would have like to see the seating depth results compared for consistency as that shows on the target.

 

[Oldbloke]

The point is, that "over annealing" is basically mis information. To over anneal you would need to be on LSD.

There is a HUGE window.

 

[JFrank]

The video is more of an answer to a jackass challenge, he said specifically he wasn’t going to shoot them.
I’m think that drastically reduces your implied huge window.

just my two cents.

 

[Syncrowave]

Shoulder should be annealed as well as the neck. (Not sure how one could anneal the neck without annealing the shoulder, considering how thermally conductive brass is.) If you keep the flame on the neck / shoulder area, it's pretty easy to observe the color change moving back into the case.

It's back near the head where you want to keep the heat away from. If you ever see the color running back too far, too fast into your case, just drop it into cold water. (Unlike steel, brass does not harden with quenching.)

Over-annealing -- If the brass turns pinkish, that means you drove off the zinc in your brass. Bad juju. (Google: de-zincification.) It also likely means you kept it in the flame long enough to anneal the head. Also bad juju.

 

[DLT]

Shoulder should be annealed as well as the neck. (Not sure how one could anneal the neck without annealing the shoulder, considering how thermally conductive brass is.) If you keep the flame on the neck / shoulder area, it's pretty easy to observe the color change moving back into the case.

It's back near the head where you want to keep the heat away from. If you ever see the color running back too far, too fast into your case, just drop it into cold water. (Unlike steel, brass does not harden with quenching.)

Over-annealing -- If the brass turns pinkish, that means you drove off the zinc in your brass. Bad juju. (Google: de-zincification.) It also likely means you kept it in the flame long enough to anneal the head. Also bad juju.

I don’t believe that

 

[Rewinder]

TECH TIP–Neck Tension vs. Time « Daily Bulletin

This may surprise you. We've learned that time (between neck-sizing operation and bullet seating) can have dramatic effects on neck tension. Controlling neck tension on your cases is a very, very important element of precision reloading.

bulletin.accurateshooter.com

 

[Bottom Fodder]

I don’t anneal and from a long range Benchrest shooters perspective, take this as you will.

I never see neck OD spring back even after a couple months, I burnish the layer of left over carbon with a bore brush just prior to seating to get remarkable seating consistency.
My observations:
Bullet hold variation changes targets, seating depth from shoulder to bullet ogive changes targets but a thousandths of headspace doesn’t seem to make any difference unless the case won’t chamber freely or extract leading forcing a bolt open.

Thanks for posting this,I have experience the same

 

[Webster]

Shoulder should be annealed as well as the neck. (Not sure how one could anneal the neck without annealing the shoulder, considering how thermally conductive brass is.) If you keep the flame on the neck / shoulder area, it's pretty easy to observe the color change moving back into the case.

It's back near the head where you want to keep the heat away from. If you ever see the color running back too far, too fast into your case, just drop it into cold water. (Unlike steel, brass does not harden with quenching.)

Over-annealing -- If the brass turns pinkish, that means you drove off the zinc in your brass. Bad juju. (Google: de-zincification.) It also likely means you kept it in the flame long enough to anneal the head. Also bad juju.

It's impossible to anneal the case head. Pink doesn't mean zinc is being burned off.

From the AMPS website;
I have not seen, experienced or found reference articles that discuss dezincification of brass under heating conditions alone. All avenues point to dezincification in the presence of certain chemicals either on their own or in solutions.

The flame color changing while annealing doesn't indicate over annealing or the Zn being burned off.