Will brass "grow" after resizing?

[Lefty Trigger]

I resized about 40 pieces of .243 brass a couple of days ago and made them up yesterday. Went to the range last night and noticed about 2/3rds of them were tight closing the bolt. Well this morning I resized 30 more right to the exact size I want 1.567 and checked everyone as I went. About an hour later they are 1.571 or 1.572! Run them through again and they go back to 1.567 wait about 15 minuets and it is already longer 1.569.
Personally I think I might have trashed this brass annealing on my own with the torch/water bucket method (http://forum.accurateshooter.com/threads/annealing-my-own-brass-look-ok.3957223/#post-37274131) Could this the cause of this??

 

[dkhunt14]

If I had had to guess they are not annealed. They might be springing back. If the anneal time isn't enough, you get no annealing. Matt

 

[Mikemci]

How many seconds were they in the flame?
Did you use templaq?

 

[jepp2]

Well this morning I resized 30 more right to the exact size I want 1.567 and checked everyone as I went. About an hour later they are 1.571 or 1.572!

Regarding the annealing, you either:
- didn't anneal long enough, so you had no affect on the case
- you annealed them perfectly and returned the case neck/shoulder to the as new condition
- you seriously overheated them and made them dead soft and they will have no spring back

For the "growth" you are seeing in the case head to datum measurement (and I have never experienced anything even close to that). You might try this: When you run them up in the die, pause 5 seconds at the top, drop them down and rotate them 180 degrees and repeat. Then measure them after you finish and 15 minutes later.

 

[grovey]

Sounds as if their too hard? Maybe lose the water bucket quench and let a little more heat get past the neck shoulder junction.

 

[foxguy]

I resized about 40 pieces of .243 brass a couple of days ago and made them up yesterday. Went to the range last night and noticed about 2/3rds of them were tight closing the bolt. Well this morning I resized 30 more right to the exact size I want 1.567 and checked everyone as I went. About an hour later they are 1.571 or 1.572! Run them through again and they go back to 1.567 wait about 15 minuets and it is already longer 1.569.
Personally I think I might have trashed this brass annealing on my own with the torch/water bucket method (http://forum.accurateshooter.com/threads/annealing-my-own-brass-look-ok.3957223/#post-37274131) Could this the cause of this??

Curious, How many times had this brass been fired before annealing, and resizing?

 

[Lefty Trigger]

If I had had to guess they are not annealed. They might be springing back. If the anneal time isn't enough, you get no annealing. Matt

After talking with an "old timer" that has been reloading longer than I have even been alive, that's what he thinks.... not actually annealed enough and brass is springing back.

 

[Lefty Trigger]

Curious, How many times had this brass been fired before annealing, and resizing?

My plan is to anneal the brass every 4th reload. These have been reloaded 4 times and then annealed and I FL resize every time bumping the shoulder back only .002. This will be the 5th reload on this brass. Seems they might not have been annealed enough.

 

[cw308]

I never got into annealing brass , I think it does more harm then good , just another thing to worry about , or blam for a poor group . I'm a benchrest rest shooter only . Full length size every firing to .0015 to .002 headspace no more or less . I got 25+ reloads out of a 308 case .

This season I'm alternating three groups of 30 cases , Shooting 30 each range trip . This is going into the fourth go round , the last season would be the 10 reload on the same cases . My feeling is brass has a certain life span , just like a barrel . Once a barrel is shot out you'll never get a tight group any longer . I'm testing to see if brass works the same way .

Last season the brass was holding up fine but when I saw a slight crack on the case mouth I dumped the 30 . This time the three groups of brass are grouping very well with consistent tight groups . I'm not changing anything . Same bullet , powder charge , everything the same . I can tell you shooting is more enjoyable , only paying attention to shooting form . So many variables in reloading adding heat to the shoulder & necks I would have put my head through the wall along time ago .

Chris

 

[grovey]

If you annealed your cases would hold up till the primer pockets gave up.

 

[riflewoman]

Ok... for the uninitiated. Metals don’t creep at room temperature unless there is a huge stress involved. A resized case only has the internal stresses left after sizing. That much internal stress is difficult to establish even in the most cold worked brass. We’re talking 0.004 inches here. I resized 3x fired brass 20 years ago and I still have the same reading as when resized. Either the resizing setup isn’t what it purports to be or there is another problem. Oh, and if you didn’t anneal them correctly, they’d be even less likely to creep.

Something else is going on here.

 

[Lefty Trigger]

Ok... for the uninitiated. Metals don’t creep at room temperature unless there is a huge stress involved. A resized case only has the internal stresses left after sizing. That much internal stress is difficult to establish even in the most cold worked brass. We’re talking 0.004 inches here. I resized 3x fired brass 20 years ago and I still have the same reading as when resized. Either the resizing setup isn’t what it purports to be or there is another problem. Oh, and if you didn’t anneal them correctly, they’d be even less likely to creep.

Something else is going on here.

Don't really know what it could be? They have all resized fine till I tried annealing them. My friend took 20 cases and it going to anneal them in his salt pot so we can see if that helps. I also just tried 20 myself using the resizing method mentioned above, resize, hold, rotate, resize again and that does seem to be working but I never had to do that before. Oh this is Winchester brass....

 

[cw308]

Never liked Winchester brass , on the thin side . May be better for velocity . I like thicker brass , HSM , FC and ADI . When annealing does thickness brass form better or worse . Did you have the same problem with other brands .

 

[riflewoman]

Don't really know what it could be? They have all resized fine till I tried annealing them. My friend took 20 cases and it going to anneal them in his salt pot so we can see if that helps. I also just tried 20 myself using the resizing method mentioned above, resize, hold, rotate, resize again and that does seem to be working but I never had to do that before. Oh this is Winchester brass....

Resizing with a pause at the top of the stroke might be your solution to the issue. Depending on the design of the press it might have enough spring in the whole system to give odd results. But 0.004 means there’s a sizing issue not a brass issue.

 

[Richard Coody]

I resized about 40 pieces of .243 brass a couple of days ago and made them up yesterday. Went to the range last night and noticed about 2/3rds of them were tight closing the bolt. Well this morning I resized 30 more right to the exact size I want 1.567 and checked everyone as I went. About an hour later they are 1.571 or 1.572! Run them through again and they go back to 1.567 wait about 15 minuets and it is already longer 1.569.
Personally I think I might have trashed this brass annealing on my own with the torch/water bucket method (http://forum.accurateshooter.com/threads/annealing-my-own-brass-look-ok.3957223/#post-37274131) Could this the cause of this??

brass springback on work hardened brass can make it difficult to get a consistent bump but a gradual change after sizing is something i have never heard of. obviously you are measuring base to shoulder datum?

 

[Texas10]

If you're going to salt bath anneal, be sure to go deep enough to anneal the shoulder area. I prefer this method for getting a good, consistent anneal. And I suspect annealing is the issue here, perhaps coupled with a die that is not a good match to your chamber in the shoulder area.

 

[Webster]

I resized about 40 pieces of .243 brass a couple of days ago and made them up yesterday. Went to the range last night and noticed about 2/3rds of them were tight closing the bolt. Well this morning I resized 30 more right to the exact size I want 1.567 and checked everyone as I went. About an hour later they are 1.571 or 1.572! Run them through again and they go back to 1.567 wait about 15 minuets and it is already longer 1.569.
Personally I think I might have trashed this brass annealing on my own with the torch/water bucket method (http://forum.accurateshooter.com/threads/annealing-my-own-brass-look-ok.3957223/#post-37274131) Could this the cause of this??

Maybe you need to bump the shoulders a little more? Is it possible your borderline jamming the bullets. Try seating the bullets 5 thou deeper.

 

[Daerider]

Honestly, the first thing I would do is change the batteries on your digital calipers! And make sure that they are accurate and consistent before you do anything else. The numbers that you are reporting do not make any sense. I have had cheap calipers give off inconsistent reading like you are reporting here. I tend to just toss them when I cannot trust the readings anymore.

 

[riflewoman]

Yeah Here is a snapshot of some creep data published here way back in the 1960s. https://nvlpubs.nist.gov/nistpubs/Legacy/MONO/nbsmonograph101.pdf

There are couple of samples that might be of interest. There is one at 84%cold drawn at 400F and one at 37% at 300F. The way to read this is that it takes the applied stress of “Y” to give the creep strain of “X” . 50000 psi applied stress give about 1 millionth of an inch per inch per hour. So .004 inches of creep on a 1.5 inch basic dimension at this stress and temperature would need about 111 days to complete.

So there’s something else going on here.

 

[Webster]

Yeah Here is a snapshot of some creep data published here way back in the 1960s. https://nvlpubs.nist.gov/nistpubs/Legacy/MONO/nbsmonograph101.pdf

There are couple of samples that might be of interest. There is one at 84%cold drawn at 400F and one at 37% at 300F. The way to read this is that it takes the applied stress of “Y” to give the creep strain of “X” . 50000 psi applied stress give about 1 millionth of an inch per inch per hour. So .004 inches of creep on a 1.5 inch basic dimension at this stress and temperature would need about 111 days to complete.

So there’s something else going on here.

Real data. I guess this means the theory that brass takes a set if you hold it in the die longer is FAKE NEWS.