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AMP Annealer stretching brass???

232593

Ruining your democracy
Full Member
Minuteman
May 25, 2022
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I annealed some more once fired Peterson .375 Cheytac Brass this weekend. On my desert tech the distance from base to shoulder is 2.538” for once fired brass. After Annealing it was 2.546”. And the base of the case is so wide that I have to hammer the bolt open to get an unfired piece of brass to extract. The code that AZTEC generated was 0156.

Anyone ever hear of this happening or had it happen?
 
I had issues after about 5 reloads on 338 Lapua brass and my AMP making the necks so thick that they would not chamber with a loaded round. Don't want to get into neck turning, so I am starting over with new brass.
 
I had issues after about 5 reloads on 338 Lapua brass and my AMP making the necks so thick that they would not chamber with a loaded round. Don't want to get into neck turning, so I am starting over with new brass.
This was once fired Peterson brass. I hope it does not do the same to my .408 brass. I’m on my 5th fireing with one lot
 
Then you have an error in measurement.
I checked it multiple times. And the unsized annealed cases won’t chamber. Bolt won’t close.

It never does anything like this with the other calibers I anneal.

What else could stretch the brass like that?
 
What happens if you perform all the exact same procedures for brass prep and loading, but just skip annealing.
I set the shoulders back .002 and everything works fine, bolt closes fine and no extraction issues, with my .408. This is the first time I annealed .375 brass. Tomorrow I will try .375 without annealing and post results.
 
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I checked it multiple times. And the unsized annealed cases won’t chamber. Bolt won’t close.

It never does anything like this with the other calibers I anneal.

What else could stretch the brass like that?

It could be warping the case shoulder, making it out of round or elliptical In shape which will change the spot where the comparator touches throwing the reading off.
 
It could be warping the case shoulder, making it out of round or elliptical In shape which will change the spot where the comparator touches throwing the reading off.
How do I fix it?
 
Can some distortion of the cases be seen with a straight edge? If this is something measurable/visible I'd say it's a contact AMP to ask for help issue.

The issue is bizarre to say the least.
 
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Just to confirm, you are using pilot #56 with 056 A pilot settings when running AZTEC analysis?
 
I did that and it still barely chambers and extracts. I’ve set the shoulder back .004 under the fired length and it’s still no luck. Even when I set the die to cam over the base is still to large to get into the chamber with out muscling it.
 
Some things else is going on. Annealing cases doesn't make them bigger in any sort of way. You just notices this after annealing
Yes and it did not just stretch the length the body/ base is expanded too.
 
Do you have any 375 brass that you haven't annealed to take measurements from? Then take that un fired brass and anneal it and I bet those dimensions don't change. I can't help with the cartridge your reloading for because I have zero experience with it but I don't anneal brass and I have to see any dimensions change after annealing. It's not the annealer, start looking at other things. Do you have a sloppy chamber that is blowing the case walls out and the die can't size it down far enough? Do they make small base dies for 375 cheytac, I have no idea there
 
Do you have any 375 brass that you haven't annealed to take measurements from? Then take that un fired brass and anneal it and I bet those dimensions don't change. I can't help with the cartridge your reloading for because I have zero experience with it but I don't anneal brass and I have to see any dimensions change after annealing. It's not the annealer, start looking at other things. Do you have a sloppy chamber that is blowing the case walls out and the die can't size it down far enough? Do they make small base dies for 375 cheytac, I have no idea there
I don’t think that the chamber is too sloppy. Once fired, unsized, and non annealed cases fit in the chamber just fine. It’s the sized and annealed ones that have the problem.
 
Measure the un annealed cases. Take multiple measurements and then anneal them and see if they grow. They should not, do and let's see
 
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Have a look at these scoring marks. They only showed up on the part you see here but they are on most of the case body.
C9A727D4-14FC-46D7-AD07-73CED94DD4B5.jpeg
 
Measure the un annealed cases. Take multiple measurements and then anneal them and see if they grow. They should not, do and let's see
I measured several once fired non annealed cases and this is what I get. When I get home tomorrow I will have to sort the other lot, find the median case, anneal a couple of them and post results.
385A345E-D89F-4857-B22E-86D5407AAE39.jpeg
 

Thats what your chamber looks like on the inside. When you fire the round the case seals the chamber and whatever imperfections are on the chamber walls get imprinted onto the case. The case tarnishes. When you run the case in your sizer, the die takes the tops off the peaks and what you see are the tarnished valleys.
 
Still trying to get my head wrapped around this.
Just to be clear @232593 ... you're saying a fired, sized case chambers just fine ... but a fired, annealed, sized case does not chamber.
Is that correct? If that's true, then I simply don't have a friggin' clue about what's causing that.
I'll be REALLY interested to see the answer to this one.
 
i was going to suggest taking three pieces of just fired brass marking each measuring each run one through the anmealer then resize , one through the resizing die then anneal and one no anealed just resized , and measure all of them till you have three pieces of brass that have been put through your process see which gives you the length you want + doesn't stretch out on you best of luck I funny enough have not run into any reason so far to run my annealer yet I am going to try it on my next batch run of brass to see if it really makes a differance for me .
 
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I've never used an AMP and I don't own any of these bigger ELR cartridges, but I recall listening to a podcast of some sort (regarding ELR) and they were complaining about the same thing. That being excessive spring back in the brass itself.

I can't recall who said it (I think it was Litz) but it was in the context of "cost" to shoot ELR and how they were using new brass because they said it was too much trouble to control sizing in these bigger cartridges.
 
Another thread on the hide I saw there is multiple reamer prints for this cartridge, A, B, C, D, E, and F and some brass doesn't fit in all chambers which is retarded. I don't see how annealing the brass would allow pent up brass spring back to release because I don't believe there is such a thing, there isn't any stored energy in a brass case to allow this to happen. Either way this thread peaks my interest even tho I will never shoot 375 gaytec
 
I was thinking of something along the same lines, that there must be some sort of mis-match between the chamber and the dies going on here... but the annealed doesn't typically affect - or it shouldn't - the brass down by the case head.

I've had some weird case size issues over the years... I'd suggest making a sketch of the case, labeling every data point you can reasonably measure - headspace, case head diameter, case web diameter, shoulder diameter, neck diameter at both mouth and shoulder, case length...

Then write them all down in a table. Virgin brass (if you have it), once fired, etc. for every step in your annealing & sizing process. Somewhere in there you'll see the critical dimension that is changing and messing things up. And it'll be a lot more coherent than trying post pics of you measuring headspace.
 
I think he’s trying to say that an annealed unsized case won’t go back into the chamber.
That is correct. And even after sizing it still will not chamber. I’m sending Peterson a sample of the brass to get their thoughts.
 
It looks like you might have a burr in the chamber from the looks of those scratches
Oh great, another issue with this barrel. Once I get this brass thing figured out I’ll have to get that addressed too.

Appreciate the info
 
Likely just a case of some of the brass not sizing as well and you’re associating it with the annealing.

Just for your own sanity:

Take a piece of fired brass not sized and try to chamber it. Take notice if it won’t chamber or the effort needed.

Now size that piece down without annealing and see if it chambers properly.

Now anneal the case and see what, if anything changes.


Do this many times. You won’t see any difference that can be correlated to the annealing.

What you will end up seeing is that some brass fits and some doesn’t. Regardless of the annealing or not.

This is likely due to your sizing die being on the ragged edge of sizing down the case body and such enough. Possibly also with the hardness consistency of the brass.


Large calibers can be very touch and go with brass. Can also be a barrel/chamber wall thickness/hardness issue as well. It can expand enough to let the brass grow larger than it’s ability to spring back.
 
I am not sure if its been mentioned in this thread yet, but your FL die can also make brass grow if its not adjusted correctly. I.E set up slightly longer than the shoulder of the case.
 
I've never used an AMP and I don't own any of these bigger ELR cartridges, but I recall listening to a podcast of some sort (regarding ELR) and they were complaining about the same thing. That being excessive spring back in the brass itself.

I can't recall who said it (I think it was Litz) but it was in the context of "cost" to shoot ELR and how they were using new brass because they said it was too much trouble to control sizing in these bigger cartridges.

I believe it was one of the "No BS BC" episodes that Frank did with Litz. Litz mentioned he basically competes with virgin brass b/c resizing brass that big does weird shit and shooting virgin brass yields better results.
 
OP, what barrel/chamber do you have, a DT factory barrel? And what dies are you using?

Agree with FENIKS above, do things one step at a time in the proper sequence and let us know where exactly in that sequence you are when you cannot chamber a fired cartridge. Also, I do think it's best to clean, anneal, size in that order, NOT anneal AFTER sizing.
 
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Desert Tech factory barrel. Dies are Whidden bushing sizer die set and I also have, did not use, Viersco die set.

I normally clean, anneal, and then size.

Work had me busy till late today so I will have to try Fenix’s method tomorrow and post results. All my fired brass fits in the chamber from the other non annealed lots.
 
Have a look at these scoring marks. They only showed up on the part you see here but they are on most of the case body.
View attachment 7890573

The longitudinal marks are most likely from either a burr in the chamber, or a speck of brass galled in your die. That happens from insufficient lube. You can fix it by spinning a tightly fitted jag wrapped in fine steel wool in the die, with plenty of Kroil, but it does take some effort.

Those rings on the case are a bigger concern though. That's from a roughly cut chamber, and they will cause difficult extraction with hotter loads. It can be fixed by gently lapping the chamber with a fired case (careful not to get compound on the shoulder, or to lap the chamber off-center; this is best done by someone who knows what they're doing and has some talent with tools) and then burnishing with a steel wool jag. But it depends on the application, whether that's an acceptable fix or if the barrel should be replaced instead.

The good news is your oversized case body issue will most likely be eliminated once those rings are lapped out.
 
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I had a bad experience with Whidden dies and returned them. I use VIERSCO. The DT chamber is pretty standard, just some extra freebore.
 
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