AMP Annealer stretching brass???

[rayvandervort]

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 had a similar set of issues on a 270 win and was not annealing. It turned out to be when, in my case, I had transitioned from neck sizing to FL and the die and chamber dimensions were both in the wrong direction to allow chambering. These were cases Neck sized a few times and I had never FL sized that gun's cases. Even new brass did the same thing on once fired cases if sized FL, but did not if Neck sized. Sent dies back and they sent me new ones saying they did so even though the dies I turned in were on spec. The new dies were a bit better but still had same issue on 50% of the cases. Changing my lube also helped but never got to a good FL sizing and stuck 4 or 5 just trying to get there. Sold that gun - no more issues! I have no issues on 3 other calibers with same procedures or even less care to FL size. I did believe I was able to attribute the issue to a tight chamber just behind the shoulder at the thinnest part of taper which also showed a chattering of the finish when bore scoped which was the final observation that traded the gun in on a Magpul 6.5CM. So I went from hell to Heaven. That gun also failed to fire form properly. I had a few cases measured with comparator to Ogive that gave me a length that would chamber. Several loads and multiple rounds never got to the same length as those that were long and chambered. Again, the thought was same tight taper area of the chamber. Sometimes a problem only gets more mysterious the more we look at it, and often it is because a very small error has been undetected in some obscure un-observed piece of data. At the beginning of my final steps to what I think was the cause was "smoking" a case and coating it with magic marker and looking for the friction points. Then the borescope and internal chamber measurements with ball expanders.

 

[rottenruger]

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?

OK, don't know if my situation is the same. Plus I'm 72 with crappy memory and the Prevagen I just started taking hasn't kicked in yet, so bear with me, please.

I was having problems with some 6.5 Creedmoor brass fighting extraction, after full length sizing. I'd have to get violent with the bolt to get the spent case out of the chamber. I mean using the side of the bench to hammer the rifle down on to force the bolt. Nasty. Had to quit using those reloads.

I got on the web, of course, and started researching. This was a couple of years ago. Enter, the crappy memory. Read somewhere that I should be using a "base" sizer or a "body" sizer or some such thing. I pulled out my die case and guess what was sitting inside? A third die, which was one of these I needed. It doesn't say on the die, I checked. Can't find the case, I keep the dies in the press. So can't name it properly for you.

Anyway, I used this puppy and PROBLEM GONE. Seems I only have to use it periodically. I don't get to shoot enough, and I reload below max charge, so I don't have to anneal often either. And my brass (Hornady, Norma and Lapua) lasts forever!

Haven't had to do this on my 338LM, haven't used the cases enough yet. It's hard to find reloading supplies.

That Cheytac 375 is a dream, I get to shoot one each year at a course I go to, along with a Steyr 460. Dream guns!!! Good luck!

F J B

 

[Tristran Shandy]

t 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.

"Comparator?" What's that?

 

[6.5SH]

"Comparator?" What's that?

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I don't think Hornady offers one for the Cheytac but they do offer a blank for use with your own reamer.

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[STLSteve86]

I know you don’t want to melt another piece of brass but have you considered re-analyzing another case?

 

[EdLoc]

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.
View attachment 7890576

Are there fired primers in the cases when you are measuring them that always throws off my measurements??

 

[EdLoc]

Are there fired primers in the cases when you are measuring them that always throws off my measurements??

Knock some primers out of fired cases measure them anneal them and measure again
They should read the same unless your code is significantly off and you completely cooking it he brass ruining it

 

[232593]

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.

Took the fired brass and it chambered. 2.538”

Took non annealed brass, set the shoulder back .002 and it chambered just fine. Easier than the plain fired brass. 2.536”. Also no chamber burr markes on the case body like last time

Annealed a case. It is 3.540”. It was a bit difficult to get the bolt closed. I repeated this multiple times, same .002” stretch.

Sized the annealed cases to 2.536” and everything chambered fine and no marks on the case body this time.

 

[Bmaier69]

@232593 have you ditched the comparator and tried measuring your case length to see if your actual over all case length has grown? I would also check the neck before and after annealing. Pushing and pulling all that brass on a large caliber could store a lot of energy that would be released once annealed. Sizing seating firing all changes how it reacts the next time it is worked

 

[Lew Hodge]

Sounds like the brass is the problem; have you used other brands of brass in this caliber? Strange, as the annealing flame should not be anywhere near the base.

 

[Bellerion]

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

 

[MK20]

Took the fired brass and it chambered. 2.538”

Took non annealed brass, set the shoulder back .002 and it chambered just fine. Easier than the plain fired brass. 2.536”. Also no chamber burr markes on the case body like last time

Annealed a case. It is 3.540”. It was a bit difficult to get the bolt closed. I repeated this multiple times, same .002” stretch.

Sized the annealed cases to 2.536” and everything chambered fine and no marks on the case body this time.

If you are sizing the annealed cases and they are chambering fine, that is the fix.

It is what you are supposed to do anyway. Anneal, size, load, shoot.

If you are using a Lee press, ditch it. The linkage on those is sintered or MIM and develops micro cracks. Will randomly not size cases just enough so they won't chamber. I had one and it gave me fits for quite a while.

 

[Bellerion]

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

Gentlemen,
I am by far no expert, however I have shot on a 4 man ASA team for some years and been blessed to learn from the 3 brother's I shoot with; to that I shall only add that I have been machining for a bit over 35 years and though I now do it with computers, the practicality of cutting and forming metal remains the same regardless.
That being said I am simply going to interject a couple of variables which I believe would be worth examination. Though as of yet we have not begun to anneal our brass, with geopolitics being what they are we may be forced to start. Since that may be the case I have began an in depth study of the annealing process relational to load/caliber/our primary powders and pressures/ our standard primers, etc., etc....you guys know the drill. Please understand that in our group, between the 4 of us we are firing at range(400-1000yds) three very different rifles. 2 308's, mine being one(an FN former psr, modified it to my comfort), an 8mm Mag, and a .265 x 55 custom. I state this because the .375 cheytac and .338 Lapua Magnum are truly "different" and special creatures among the rifle community. I have found through research that we as a team should be fine and enhance at least twofold our number of reloads. I have also seen that because of the metallurgical properties of rifle brass were we to be using larger calibers and building much higher chamber pressures I would not agree that the cause outweighs the effect. Lapua is obviously the teams preference and for good reason. The Company has very stringent controls on the metallurgical composition of their base product as well as their production processes which yields what we all admire. However, brass is extremely unique in the way it reacts to its environment. We all know brass as the great material which we use to "seat a bearing, or give something a useful tap to adjust it for welding without damaging the surface we're striking" and that's all true but look at what's labeled 'Naval Brass' which is named such for its uses on American Aircraft Carriers and other seagoing vessels because of its mixture of anti corrosiveness as well as its toughness to hold up under pressure, then examine spinodal bronze which is mostly brass with a few very exceptional ingredients which yield and extremely durable material specifically in the region of repetitious action and reaction which is used highly in the hydraulic units of our Apache helicopters because of millions of repitions that their primary and redundant systems utilize. The straight answer is that, not from an expert but from one which knows metal, I would begin to examine the metallurgical properties of the brass which I was purchasing, then delve into the 'ability' of said brass to recover by annealing in order for extended reloads.
Let's face facts, my FN barrel is great but after between 6000 and 9000 rounds, I am actually breaking down the internal grain structure of its metallic composition and as it degrades it will flex and move in ways that are mathematically unpredictable which will ultimately lead to me replacing my barrel...then my journey begins all again, seating depth, powder dump, breaking in a new snout, we all know the process.
I suppose if anyone is to take anything away from my examinations, it would be first and foremost know your brass's metallurgical properties, second it appears that in the larger more powerful calibers you will find greatly increased difficulty in pinning down a great process for annealing, much akin to rebuilding a .396 big block to stay together at 8000 rpm as opposed to a .350 four bolt main which is cake, and lastly know your chamber... As I read through the comments and photos, as a labeled "Master Machinist", dod's words not mine, I can identify with the post that pointed out the score marks on the base of the brass. By optical comparator as well as experience I can assure you that by the very aspect of the process in which a reamer forms a shape it will not show its wear until it's within roughly 25% to 40% of the base of its stroke. To be more precise you will begin to see deeper lines higher above the terminus of its travel which will seem to diminish as it goes to depth and finally almost disappear at full depth wherein it will appear to be a simple band around the diameter. This is caused by what Machinist call 'lead effect' which simply means that the deeper the reamer gets into its projected axis(hole) the less it will run out from its holder and the spindle that is driving it. Note that ALL reamers,unless otherwise ordered from the manufacturer, will have a tapered or angular lead of approximately 5% which shows in the solid ring at the base of your brass plus travel of the tool...bluntly put, you should have a certified gunsmith do an impression mold of your action and place that against an optical comparator mathematical read of the tolerances of the blueprint which your rifle manufacturer should have available online.
Thanks for your time, hope this helped...
Vaelin

 

[Bellerion]

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 prob

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.

Good call. You're exactly right.

 

[Feniks Technologies]

Took the fired brass and it chambered. 2.538”

Took non annealed brass, set the shoulder back .002 and it chambered just fine. Easier than the plain fired brass. 2.536”. Also no chamber burr markes on the case body like last time

Annealed a case. It is 3.540”. It was a bit difficult to get the bolt closed. I repeated this multiple times, same .002” stretch.

Sized the annealed cases to 2.536” and everything chambered fine and no marks on the case body this time.

I’m slightly confused.

What was the case measurement before the annealing? 2.538?

And you did zero anything to the case except annealing and it stretched to 2.540?

If so, do this to like 5 or 10 cases and see if it’s consistent.


Either way, it doesn’t matter much. Just run all your brass through the annealer.

And then size it to 2.536 or whatever preference of closing pressure or lack thereof you want on the bolt and roll on.

The only reason for concern is if you anneal your cases and when sizing to 2.536 (or whatever), many of them have chambering issues. If so, and setting it to something like 2.535 or similar (to account for variances like lube inconsistency) doesn’t work, then you either have a die problem or a brass problem.

And you’ll either need a die that sizes things down smaller and matched to your chamber better. Or better/new brass.

 

[9/11]

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? The chamber is ballooning the rear of the brass ,could be a out of round chamber measure brass from front to back with a mic variation only need be .003-.007

 

[MarkyMark007]

so annealing your brass is stretching it a little.

stop worring. you will be sizing it after annealing anyway.

NEXT!

(maybe we all get larger brass after annealing, but we dont measure it

 

[232593]

I’m slightly confused.

What was the case measurement before the annealing? 2.538?

And you did zero anything to the case except annealing and it stretched to 2.540?

If so, do this to like 5 or 10 cases and see if it’s consistent.


Either way, it doesn’t matter much. Just run all your brass through the annealer.

And then size it to 2.536 or whatever preference of closing pressure or lack thereof you want on the bolt and roll on.

The only reason for concern is if you anneal your cases and when sizing to 2.536 (or whatever), many of them have chambering issues. If so, and setting it to something like 2.535 or similar (to account for variances like lube inconsistency) doesn’t work, then you either have a die problem or a brass problem.

And you’ll either need a die that sizes things down smaller and matched to your chamber better. Or better/new brass.

Correct, measurement before annealing was 2.538. After annealing 2.540”. It was done over ten times with the same result.

I think their may have been issues with the last batch of brass. This particular lot will chamber just fine after sizing and annealing, unlike the last lot.

 

[drshoot]

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?

Are you wet tumbling your brass?

 

[232593]

Are you wet tumbling your brass?

No

 

[232593]

Sounds like the brass is the problem; have you used other brands of brass in this caliber? Strange, as the annealing flame should not be anywhere near the base.

Besides Peterson I have only used Lake City. The unit does not have a flame.

 

[232593]

I know you don’t want to melt another piece of brass but have you considered re-analyzing another case?

I did anneal a different lot .015 average thickness and 382+-1 grain. Had a code of 0160. Everything worked better with the exception of .002” stretching. And it fit in the chamber before and after annealing

 

[232593]

@232593 have you ditched the comparator and tried measuring your case length to see if your actual over all case length has grown? I would also check the neck before and after annealing. Pushing and pulling all that brass on a large caliber could store a lot of energy that would be released once annealed. Sizing seating firing all changes how it reacts the next time it is worked

Did that tonight with 5 leftover cases and saw an increase of .002 in the length. But the case body did not grow this time and everything fit fine in the chamber.

 

[232593]

Just to confirm, you are using pilot #56 with 056 A pilot settings when running AZTEC analysis?

Yes

 

[232593]

Are there fired primers in the cases when you are measuring them that always throws off my measurements??

No I deprime before I do anything else.

 

[Barelstroker]

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 a similar problem when I started annealing 308 brass with the exception of the brass getting longer. I've annealed & measured hundreds of cases & never seen any change in dimension.
The problem I had was due to the softer shoulder area of the case sizing earlier in the stroke which would cause the case to be shallow in the die leaving the area above the web not sized enough.
With the 1st barrel I had, I was forced to size 0.001 to 0.002 more to compensate & get the web further into the die.
From what I can tell, it's basically a combination of the die & the chamber dimensions.
My new barrel I have installed seems to have a very slightly larger chamber web section which allows the die to size the case web appropriately.
Maybe try another brand of die & see how it goes or, have a gun smith polish a bees dick out of the lower section of the chamber.

 

[232593]

Peterson informed me this week that the annealing created a bow in the shoulder of the case causing errors with my measurements. No explanation about why the overall cartridge length grew after annealing. They detected the bow with their optical comparator. I don’t have one of those.

I used a different lot of Peterson brass to test a 390 grain ATIP behind 136 grains of RL50 and had none of the previous issues.

 

[Barelstroker]

Peterson informed me this week that the annealing created a bow in the shoulder of the case causing errors with my measurements. No explanation about why the overall cartridge length grew after annealing. They detected the bow with their optical comparator. I don’t have one of those.

I used a different lot of Peterson brass to test a 390 grain ATIP behind 136 grains of RL50 and had none of the previous issues.

In all the scientific literature I have read about 70/30 cartridge brass annealing, I can't recall any references to dimensional changes caused directly by the annealing process. My own personal experience aligns with the lack of reference to dimensional changes as well.
The only issue I've noticed was an indirect change in the shoulder position due to the softening of the brass which subsequently caused the shoulder to be pulled up by the expander ball as the ball passed through the neck.
This effect was not pronounced by any means but, it could be measured & did cause some frustration until the cause was established. I now remove the expander ball & use a sizing pin in a separate sizing stage.
Did Peterson tell you if the "bow" was concave or convex?

 

[232593]

In all the scientific literature I have read about 70/30 cartridge brass annealing, I can't recall any references to dimensional changes caused directly by the annealing process. My own personal experience aligns with the lack of reference to dimensional changes as well.
The only issue I've noticed was an indirect change in the shoulder position due to the softening of the brass which subsequently caused the shoulder to be pulled up by the expander ball as the ball passed through the neck.
This effect was not pronounced by any means but, it could be measured & did cause some frustration until the cause was established. I now remove the expander ball & use a sizing pin in a separate sizing stage.
Did Peterson tell you if the "bow" was concave or convex?

They did not. I’ll ask them tomorrow

 

[memilanuk]

They did not. I’ll ask them tomorrow

Might be worth dropping a note to AMP, if you haven't already. Seems like something they would want to know about.

 

[Barelstroker]

They did not. I’ll ask them tomorrow

Although it could be possible for you to have a similar issue with the expander ball pulling the neck/shoulder junction up, I don't believe that particular issue is a likely possibility with the AMP due to my annealing process which leaves the brass quite a bit softer than the AMP would tend to.
The other issue I've had primarily with 308 brass was also to do with the softer case neck & shoulder sizing down earlier in the stroke when FL sizing which then left the area just above the web too large which caused the cases to stick in the chamber just above the solid web. This seems to be more of a mis-match issue between the rifle chamber & that particular FLS die. Not a fault with either the chamber or the die but, because the brass is now a little softer, it will ofcourse size down more easily & subsequently slightly sooner in the stroke into the die. If the chamber is on the smallish side of spec & the case isn't being pushed deep enough into the die, the web is just ever so slightly larger than before sizing un-annealed cases.
Although I didn't get this situation with every annealed case, from memory I had tight case webs about 1 in 3 or 4.
If I were load developing, I would size the shoulder back 0.001-2" & put up with the sticky case webs or, if I were loading rounds for night culls, I would push the shoulders back 0.003-4" & that would get 95% + chambering freely.
I've never seen it as a problem perse, just something to allow for when necessary.