Brass Hardness Over Time

[Alamo]

So I am reading that brass that has just been reworked is softer than brass that has been sitting for a while after... so this leads me to several questions: 

1. Is it better to resize and seat during the same time period or better to resize and wait before seating?

2. Would seating after the brass has been sitting for a while create more neck tension or would seating the bullets work the brass, making it soft again?

3. Would seating the bullets, then waiting a while for before shooting result in more neck tension? (I’ve noticed freshly seated bullets are much easier to pull)

4. Is it better in general to wait a certain amount of time before shooting reloads to allow the brass to settle first? 

5. Obviously, inconsistencies will result from shooting batches of bullets made at different times even if all other characteristics are the same... how long before the brass settles down and time elapsed since working ceases to be a factor?

[survivalshop]

  Brass hardens with working it , Loading , firing & then resizing it , its why I Anneal all my Rifle Brass every other reloading . I used to Anneal after every shooting , but found it wasn't necessary , the Bullet tension was still very good , that & I'm not a Match or long range shooter .

  All the other things you have a concern with , IMO has no bearing on the brass case , as far as I know , because I have brass in many forms of the reloading process , sometimes for months & see no difference in processing the Brass , but nothing scientific .

[jtallen83]

I think it would be decades before any age hardening showed enough to be measureable, and then it would take meticulous measurements to quantify.

[Alamo]

“... time of loading is another key variable.”

“James Phillips discovered that time is a critical factor in neck tension. James loaded two sets of 22 Dasher brass. Each had been sized with the SAME bushing, however the first group was sized two weeks before loading, whereas the second group was neck-sized just the day before. James noticed immediately that the bullet seating effort was not the same for both sets of cases — not even close.”

“Using a K&M Arbor press equipped with the optional Bullet-Seating Force Gauge, James determined that much more force was required to seat bullets in the cases which had been neck-sized two weeks before. The dial read-out of seating force for the “older” cases was in the 60s, while the seating force for the recently-neck-sized cases was in the 20s. (These numbers loosely correspond to the amount of force required to seat the bullet). Conclusion? In the two weeks that had elapsed since neck-sizing, the necks continued to get tighter and stiffen.”

http://bulletin.accurateshooter.com/2010/02/neck-tension-bullet-seating-and-the-time-factor/

[Alamo]

I had noticed the phenomenon when pulling bullets...didn’t have a fancy force gauge to tell me exactly how much the difference was, but it was noticeable... which caused me to do an internet search which turned up that article.

[jtallen83]

It might be relavent but the force required to seat the bullet was measured, not the neck tension and that is what counts.

[survivalshop]

      There are far too many variables to why he got the results he got. What is a 22 Dasher , how is the case formed/made , how many times were they reloaded  was it Annealed before forming ?  That use of a Dial indicator for pressure measurement is wishful thinking , no way is it the proper tool for this type of measurement , not scientific results .

  As far as your pulling of Bullets , the same can be said about the Variables , Brass make , how many times reloaded & not Annealed , The Bullet also , all manufacturers bullets are not made the same , just too many things contribute to any of these conditions . 

[bubbas4570]

Those measured results only matter if he had measured EVERYTHING that he used, exact brass/case wall thickness, exact bullet diameter, even having a slight burr in one case mouth can change out readings....

I didn't read the article, but that is what I thought of first off.

[Alamo]

Found this thread discussing the  issue, they stay on the topic of brass elasticity over time, and discuss the mechanisms... then they go off on a tangent and argue about incidents of bullets sticking in the necks and what the reason is exactly.

http://forum.accurateshooter.com/threads/neck-tension-changes-with-time.3792938/page-3

What’s a .22 Dasher? And who is this James Phillips guy?

“A while back James Phillips set out to build a rifle for the Annual Hickory, NC Ground Hog Shoot. Working with Mike Bryant, he ended up with a rifle that was more than just a first-rate varmint-slayer. His Bryant-smithed 22 Dasher turned out to be one of the most accurate rifles ever made. Competing in registered IBS 600-yard matches in the fall of 2004, James set three IBS world records with the gun, earning top marks for both Score (55-5X) and Group (1.174"). Veteran long-range shooters tell us that a gun that can group in 1.25" at 300 yards should be competitive. Well, James beat that--at double the distance. James' amazing 1.174" 600-yard group works out to 0.19 MOA. To do that at more than one-third of a mile is a major achievement.”

http://www.6mmbr.com/gunweek030.html

[survivalshop]

     I'm no metallurgist , but its no wonder the Brass case is relaxing or hardening , I wouldn't use this Case as a rule for any normal made Cartridge brass , it may well describe what happens to a case formed to those tolerances . Just look at the case & how its necked down .

    Brass is funny stuff & sometimes , like all metals, has reacts to being stretched or manipulated . You can't compare this specially formed , wildcat cartridge to any normal cartridges that are not subjected to this treatment . Not taking away from his world record ,  he's a good shooter & made a good cartridge & Rifle  , for that specific match , but it doesn't relate to normal reloading . Like I said , too many variables to compare this cartridge to any I use & no real scientific data .

     The Annealing of the worked Brass Case is what will allow the Brass around the Neck area to soften up from its firing case hardening & this is what lets the sized case Neck to conform to the Sizing procedure for proper neck tension  , with out Annealing the case Neck will spring back instead of conforming to proper Sizing Spec's . There are many articles about this everywhere from many sources , including world record holders & long range shooters .

   JMO 

Edited October 1, 2017 by survivalshop

[Alamo]

After condensing all the BS and back and forth sniping about irrelevant topics in those threads on the Accurate Shooter forum... I think this is the most reliable takeaway:

Brass (or any metal for that matter) springs back in the opposite direction that it was last worked.

That sounds about right to me anyways. I have a buddy that’s an engineer that used to work for US Steel, will see if I can get him to give an authoritative confirmation on it.