Annealing, Grain Structure

[BobCat45]

hounddawg,

I used molten salt to fix temperature, so I could let use time as a variable. Unless the contorller goes bonkers the temperature is not going higher than the setpoint, so the effect of time can be easily sorted out.

You are right it is not for "at home" but mainly because once it cools, the salt attracts moisture and gets corrosive. If you let it cool and cap it, no problem. And if you minimize the volume, the fire risk gets manageable. And keep organic stuff away from hot nitrates.

A lead bullet caster might be tempted to fill a little stainless steel dessert cup from Walmart with mixed nitrate salts, float in his melt, and dip case necks...

My boss is cool - he knows that if I'm in the lab for a 'government (of, by, and for the people) job' that I will do some 'actual' work, too - but he thinks we're nuts to even bother to reload fired cartridges. Think of a guy who throws away the wood stick from his ice cream bar, then has to find a nail or ballpoint pen to mix his J-B Weld.

But I bet the deer he puts in the freezer every year tastes better than an MR-1 target with cardboard backer, no matter how you season it. More nutritious, too.


RC20,

No new, unfired LC 84 case, but I found an LC 13 case with primer still crimped in; once-fired so not pristine, but minimal cold work.



Microstructure and hardness - 122 HV500 - is not far off the "torch" one - a few points Vickers is nothing, a few points Rockwell C means lots.


JeepHammer,

Used Vickers because it is what I have. Nice to put the indenter midwall on the cut face, with nothing under it but brass (not testing the anvil).

Full disclosure - it takes a few tries to get the indenter centered, in a properly etched area, to take a "nice" picture - so the pictures are selective. But it takes comparing a couple of Vickers readings on the same sample to trust that the one you are photographing is actually "right".

I'm convinced that anything you do - flame, induction, or hot salt - to get the neck to the proper temperature, for the right time, will work fine. And if I were shooting a unique or hard to come by cartridge I would for sure be annealing necks.

But .223 brass is cheap, lasts around 8 firings before the neck tension gets iffy, and after that it is still good for standing practice. When I shoot a 7 standing it is because I jerked, flinched, or lost focus - not because of non-uniform neck tension!

[Unclenick]

BobCat45,

Thanks for sharing all this. I do, however, think doing a selection of new brass, just to see what the manufacturers have found to be optimal, would be worth seeing. If you can't bear to sacrifice any, PM me. I'll take the hit and send you some sacrificial lambs.

[hounddawg]

Bobcat, thanks again. I will chime in with Uncle Nick and volunteer a couple of fresh from the box Lapua cases if you want them to test. Just msg me with a address and I will fire them off to you

I agree with you on annealing the rare brass vs common stuff. Unless you are shooting at range where a 50 FPS difference will move the bullet 2 or 3 inches or shooting cases which are rare and costly I would not bother with it at all

I briefly looked into the molten salt bath method using a lead pot but decided that it was just too risky to try at home. I will leave that along with grain analysis to the pros.

This week I will start doing some testing of my own annealing efforts. I don't have access to any lab grade testing equipment so I will use what I have, my rifle and a chrono. A couple of hundred rounds will not be enough to prove or disprove anything statistically but will be sufficient data for me to make a thread with what I find and decide if I want to pursue it further. I should be finished by August

[Metal god]

As per unclenick , ill send a few new lapua cases . PM me if you want

[BobCat45]

Happy to do it! I post infrequently because everyone here knows more about shooting than I do - someone always answers better than I might. So doing something I know about will make me feel less of a parasite.

Let's define a goal / plan for this. I do not generally buy brass new, that's why I have no new brass to contribute. One case from any particular brand/year/caliber will furnish several neck specimens, and I can get micros and microhardness on one specimen.

So if we want to know what a new, Brand X, caliber Y neck looks like, that takes one case. Same for N-times fired, Brand X, caliber Y, and so forth.

Let me know what we are after and I'll PM my address.

Note that this is predicated on my doing the work off-hours, time and Management permitting, and limited by intrusions of Real Life (e.g. Wife to doc, dog or cat to Vet, truck down for parts, WWIII starting, and so forth).

[Metal god]

I don't know of the amount of work involved but I'm willing to send what ever is needed of what I have .

Example :

I have virgin 308 Lapua brass as well as once fired from the same lot# . I could send one of each to see what the difference may be .

I also have 5.56 once fired LC brass and 5 times FL sized , loaded and fired of the same year . Not sure if from the same lot though .

As well as 308 WCC-06 brass that has been FL sized , loaded and fired 8 times and annealed using the torch and socket method after the fourth loading . I believe I have a piece that is still only once fired for comparison but I'd need to check on that to be sure .

I'll let you smarter folks figure out all the parameters , Just tell me what you want sent

[hounddawg]

I'll let you smarter folks figure out all the parameters , Just tell me what you want sent

ditto for me, I can offer a piece of either brand new or used Lapua .308 or .260 Remington or any combination. I understand the time constraints so if you only want to do one or two pieces of the new stuff just to have a standard with which to compare.

Doing one would give us the data for a new Lapua, data from two cases from 2 lots would give data on the consistency. Just my thoughts at least, I would defer to judgement of the more experienced people here

[Unclenick]

I have samples of Lapua, Norma, LC, IMI, Winchester, Remington, Federal and the new Starline .308 brass that are new and never-loaded. Probably more than that, if I go poking into corners, actually. The three of principle interest to me would be the LC, Lapua, and Norma. They all have good reputations so they presumably all do a pretty fair job. Part of Norma's QA program is to randomly sample cases and make sure they survive at least 10 reloadings (or 10 loadings, with 9 being reloads—I forget which) without neck splits, so they must have a good handle on optimizing the partial annealing process.

[Metal god]

Originally Posted by Unclenick

The three of principle interest to me would be the LC, Lapua, and Norma.

UN I'd like to see Federal added to that list . Only because we've all heard how it's softer . I'd like to see how they compare to Lapua and others .

[Unclenick]

I think all the hardness complaints are about the head (primer pocket growing too easily). I don't know that the necks are particularly different from other makers. That said, their match ammo has such a good reputation that knowing what they use at the necks would, indeed make it a good choice.

[JeepHammer]

Most certainly hard to hit a prepaired microstructure area with a hardness tester!
A cross section of a side wall is almost impossible to hit.
You are correct about NOT testing the anvil! Made that mistake myself!

I usually don't do hardness punch on the microstructure sample since I usually mount samples and the mounting materials don't lend themselves well to punching.

You stepped up the game!
REALLY good work!

[BobCat45]

Metal God has 308 Lapua brand new and once-fired...

and 5.56 LC - once-fired and 5 times resized. I think we kind of have this covered already, I posted once-fired and 8-times fired LC.
He also has 308 WCC-06 8-times fired and torch annealed and might have once-fired.

hounddawg has 308 Lapua

Unclenick has Lapua, Norma, LC, IMI, Winchester, Remington, Federal and the new Starline .308 brass

The common thread is 308 Lapua.

I propose that we go with the eight makes of 308 that Unclenick has, since it includes Lapua, and see how that goes.

I'll PM Unclenick my address right after I post this.

JeepHammer - no possible way in the world I could drop an indenter midwall in a case neck in a mount, freehand! If I were steady enough to do that, every score would be 200-20X - which, believe me, they aren't.

The microhardness tester has an X-Y table, with micrometers, that holds the mount face up. Imagine a miniature vertical milling machine, with a turret with indenters and objective lenses where the tool chuck would be. Only thing makes it hard to hit the exact midwall is minor inexactitude in the detents of the turret.

You can Google "Wilson-Tukon 230 image" to get an idea what it looks like.

Also see http://www.gordonengland.co.uk/hardn...rohardness.htm for a pretty good writeup.

You can use a microhardness tester to measure things like case depth on carburized or nitrided parts. If the specimen has any size there is metal below the surface of the mount. And if you are interested in what is happening at the edge, that's one instance where the "specialized" hot-mount phenolic or epoxy is advised, otherwise the hobby-store clear styrene you mention is totally good enough (and cheaper!).

Somehow I think F. Guffey is right that the real proof of the pudding is measuring the force to pull a seated bullet and looking for variation.

[JeepHammer]

I could never do it, that's why my samples are outside sidewall samples and not edge samples.
Some guys do inside sidewalls, I tried it, but it's just so much easier to hit the outside of the case,
MUCH bigger target for my old eyes and production equipment.... (Sucks getting old! I used to be able to read the microprinting on $100 bills, now I need longer arms & stronger glasses to read a large type menu!)

Good shots of microcrystalline (too hard) and mono-chrystaline (your 'Too Soft' image),
I don't know what microscope you are using, but it takes pictures clear as a bell, and your smaples are virtually perfectly prepped! Excellent work, and that's coming from someone that's actually tried to get my samples that good looking!

Did you say you were finishing under half micron? Are you using diamond abrasive in that finish?
If so, what kind and is there a common abrasive out there that is equivalent?
My finishes are with stone lapping compound, cheaper but doesn't give that clean of cut..
Your etching treatment is second to none, I may have to invest in some scientific grade etchants.

I bought the cheap polarized filters and they produced crap all around...
I see the pictures come back from the (proper) lab and the grains jump out at you!
I can't even come close with my low budget equipment, and I'm butt hurt about the $800 unit for the microscope I have just for a hobby job. Maybe someday I'll stumble into Leica polarizing kit for mine, but not today...

[JeepHammer]

Also, don't take it wrong, Vickers machine is what I should be using instead of Rockwell.
I have a calibrated Rockwell, so that's what I use.
Although the conversions are a pain, it's pretty accurate & it's paid for!
My required lab samples come back VERY close to what the shop done samples tested out at.

When you mention leveling on a pointed indenter, that's when I know you have pulled your hair out more than once!
Not a lot of material there to get 'Flat' in the first place, and getting the sample flat spot level in the machine is mind numbing sometimes!
There is a reason I'd rather be cutting metal or shooting than doing this QC stuff!

[RC20]

I can throw in once fired PPU.

I am interested in that, its all I hve in 7.5 Swiss and I have 200 or so each in 308 and 30-06.

It seems to do well.


: The FC soft seems to do more with cracked bases (for me) than anything else.

Even with some careful shoulder bumping it occurred.

I don't know if it was fired in just a single rifle though.

Its nice to work with, primer pockets did not get loose but 8 firings was the limit.

[BobCat45]

Forgive me for resurrecting this old thread, but there is unfinished business.

Unclenick sent me the cases he said, and it took me a few weeks to do the neck micros. Then micros and hardness near case heads. Then macros of the case heads, showing where the micros were taken, which did not turn out very well. Then we both got swamped with other work.

Unclenick has the pictures and is organizing them, doing some image enhancement, and putting them into a .pdf file.

But I am vain enough to wish not to be thought of as someone who makes promises and does not deliver.

So the raw images are at https://postimg.org/gallery/17w782rnu/

[JeepHammer]

I look forward to context with these pictures!

[Unclenick]

When I get done with the listing they will go in a new thread as a sticky at the top of the forum. You will see the measurement results, and while a sample of 1 each doesn't give you a good average, collectively, all but a couple come pretty close on the neck numbers and averaging those close numbers probably makes for a good target value.

[JeepHammer]

Broken links!
Did this ever get done?

[BobCat45]

JeepHammer, they've changed their website.

The new link is https://postimg.cc/gallery/17w782rnu/ and if they vanish again, let me know. I have the micros on my computer and on a backup drive - it was a lot of work and, although I've missed being laid off so far, the prospect of re-doing it is slim.

[JeepHammer]

That is WONDERFUL work!
Those are every bit as good as the micrographs I paid a ton for.

Thanks for doing this, I know how much work it was! Simply outstanding!

[T. O'Heir]

Things a little slow where you are?

[F. Guffey]

Things a little slow where you are?

T. O'Heir. slow? Not around here. Many years ago I did a 'little' research on something I called 'rules of annealing'; based on the rules I made a few tools for annealing.

Based on what I have seen across the Internet I have to wonder, I have never seen a reloader do anything different; So, I assume they all follow their own rules.

F. Guffey

[hounddawg]

Appreciate the hard work by Bobcat and while the lab studies are interesting it tells me nothing about what happens at the firing line.

If you look at any reloading forum you case find scads of opinions on the benefits of annealing your cases. But they are just that opinions, nothing scientific just hand me down wisdom and hearsay. The blogs and magazines have tests that will tell you that such and such machine or tool will get your cases hot but have no info on what affect they had on the cases when actually fired. What I want to see is the shooting bench range testing of annealed versus non annealed cases over the couse of multiple firings and the affect on velocity consistency and case life.

Litz did a short segment in Modern Advancements in LR Shooting Vol 2 but only tested .223 and .308 over the course of ten reloads. He found no difference in the .223 or the .308 during the ten firings comparing annealed after every firing and never annealed cases. He used the AMP annealer but used settings for the wrong case manufacturer or lot # for his .308's so called that test invalid. He has promised to undertake a more indepth study for Vol 3. His initial test showed no duifferences in any way between annealed and non annealed cases

One would think with all the interest in the subject someone on one of the hundreds of shooting blogs would do a similar test on annealed versus non annealed cases over a course of 10 or 20 reloads. That no one has done or ever published such a study leads me to believe that annealing for reloaders is simply theory and snake oil. Preach me the theory all you want but the lack of real world at the shooting bench testing speaks volumes.

Before tar and feathering me and running me out of town on a rail for blasphemy keep in mind I still anneal every firing using an Anealeeze. Currently I regard it as a rabbits foot more than something actually needed. If my machine died tomorrow I would not replace it until I see a shooting bench study showing it positively affects my velocity consistency or case life in the real world.

Also keep in mind I am addressing this from the standpoint of the average shooter not a manufacturer or someone that does wildcatting were the metal undergoes radical changes in shape.

[BobCat45]

Hounddawg,

Annealing lowers the yield strength so that the neck does not resist resizing as much as it would if it were not annealed. This allows the neck to be made smaller, so neck tension can be restored more effectively.

I have lots of well-used .223 brass with poor neck tension that I use for standing practice - single load, single fire - because I do not trust it to resist bullet setback cycling in an autoloader.

Or I give it to friends who cut it down to make 300 Blackout. They can look in the cut-down cases for incipient case head separation.

Annealing also eliminates some of the cumulative effects of cold work, allowing the brass to be fired, resized, reloaded, and fired again, more times before the necks start to crack.

I do not anneal, but if I did I would probably use a molten salt bath at relatively low temperature (e.g. 800ºF) so the time-at-temperature would not be so critical.

Any shot that I shoot that is not a 10 or an X is because of my poor technique (trigger control or wind reading), not because the brass was not annealed.

Opinion: annealing is about making the cases last longer, not about increasing accuracy of the loaded rounds.

It is only my opinion because I have not made a controlled study, or read (found one to read) such a study.