How much is too much - annealing

[BrentD]

Until recently I almost never annealed my brass for my bpcr rifles. I shoot Starline brass exclusively, and I never annealed them when they were new, never mind after each firing. After 3-4 yrs, I found a few of them growing slightly long so I trimmed them and then decided to anneal them "just to be safe", which I did by hand with a drill and torch. That was considerably more onerous than "no fun". Ever since then, that brass has shot just fine and dandy, however, and not a hint of stretch or any issues at all. It has been shot many many times in recent years since that annealing experience.


So, this past winter, Al and I decided to build a pair of 40-65 and for various reasons, we decided that Starline .45-70 brass would be used and that I would do the brass forming. So, I ordered up 1250 rounds of brass. Internet gospel is that the brass must be annealed before reshaping to .40-65. No liking my memories of the early annealing adventure I built my own automated annealing machine, which was lots of fun and did the whole bunch in about 3 hours.


Well having the machine was sort of fun so I started annealing after every firing, just to keep all the brass "the same". But suddenly, I started having trouble with cases sticking in my chambers. This was true for my .38-55 brass which I started annealing too - I was annealing everything. Well, after some careful measuring and marking cases with marking pens. I found that the issue was right at, or just below the wad where compression was causing the wad and the powder just under it to bulge the case. Whether I used LDPE wads (sort of new to me) or Walter's fiber wads, the same thing happened.


I only anneal for a few seconds. Just enough to get a faint red glow in a very dark basement. But that is enough to over soften the brass if done every time apparently.


I don't know if anyone else has experienced this. I know lots of folks anneal every time. But I'm done with that. I'll anneal on demand - like every 4+ years. Maybe.

[BK7saum]

Over-annealing softens the brass and reduces the springback. When fired, cases are more pronw to sticking in the chamber. I anneal bottleneck rifle cases every 3 to 5 firings or when neck tension from seating is inconsistent between cases. Also, heating to any red is over annealing. With an annealer, I try to anneal so that the brass changes color but doesn't glow red. Tempilaq is can be applied to cases to monitor case temp. I would back off the amount of time the cases are in the flame so that they don't turn even a dull red. Or at least don't anneal them every firing as you now plan to change.

I have annealed to a dull red before but it was after numerous firings when I started getting split necks.

[BrentD]

They don't stick in the chamber coming out. They stick going in.

Easier and better to just not anneal until it is needed.

[BK7saum]

Ok. Sounds like the frequent annealing has softened the brass so that when the wads are seated the pressure swells the cases.

I have work hardened case necks by sizing and expanding them a few times when I happened to overanneal. Normal use and sizing will work harden the cases back to a pre-annealed state

[BrentD]

Yes, that's the problem. Just up at the neck region. I won't bother with doing a lot of sizing/expanding. I"ll just shoot them and they will eventually work harden, but I have to run them about 80% of the way into the FL die to get them to chamber. This will fix itself eventually.

[rfd]

in the past i've also annealed brass because the gurus of the internet told me that was the thing to do. so i'd stick a .45-70 case in a socket in a drill and hit it with a propane torch for a few seconds each. it all seemed to work out ok, but truthfully i dunno why i even bothered with annealing. once fire formed, the brass never gets worked again and bullets are finger seated. after 40 or so firings i still haven't seen any measured case stretching, nor do i get blowback in the chamber. cartridges chamber without any drag or holdup and extract easily. one thing that might be helping with the case stretching is have really super clean case insides, where the black powder can't make a purchase on the brass to stretch it. but with all of this stuff, i dunno for sure - if it seems to work ok for the longer haul, then i guess it is ok ... ?

[BrentD]

rfd,
Exactly. It is far overrated. Fun to do with my little machine, but not necessary and sometimes counter productive.

[oldred]

Just my bit of experience with this, I am sure I don't shoot nearly as much as most of you guys do thus my cases never see as much use however my 45-90 Starline cases have never been annealed and so far have shown no signs of needing it. Neck tension seems to have, so far anyway, stayed consistent and I have gotten no signs of gas leakage except for only a trace at the very edge of the case mouth. I too was aware of the internet wisdom of the need to anneal my BP cases but I decided to just let it go until it became necessary, so far that just has not happened and until problems such as obvious gas blowby occurs I will just continue to load and shoot them as-is.

[Lead pot]

At one time I used to anneal often but I realizes that I had to trim to often so I pretty much stopped till I noticed that I started to get a bunch of vertical. This was usually after a seasons shooting in the large chambered rifles that I had to resize or taper crimp the bullets so I could handle them while on the line.
My rifles chambered with my custom reamers that will just except a bullet in the fired cases only get annealed when I get a new batch of brass. The new unfried and unsized cases will not chamber in my rifles that I used my reamers so they get annealed before I run them through the sizing die I make with the matching reamer made smaller then the chamber reamer. From there on they don't get annealed again because the case just fits the chamber and the bullet is a snug fit in the unsized case and there is no stretching problem after the brass re hardens again.

A good time to anneal is for forming bottle necked cases from basic brass or reducing cases from .45 to .40's.

[justashooter]

agreed that annealing is required when changing neck diameters by more than 10%, and good practice when changing diameters by 5%. in other cases, as the OP notes, it can be counter-productive. some case forming operations should involve multiple steps, with annealing after each, to counter the work hardening that occurs in the "drawing" of the case. 500* is a good annealing temp with thicker brass, but a flash heat of 650* applied quickly to the neck of cases and water quenched works well. this temp is seen in normal lighting as shiny blue to light grey. loose the shine or go into the dull reds and you are way too high in temp. use a cheap harbor freight infrared gauge to measure if you like:
http://www.harborfreight.com/infrared-thermometer-93984.html

it is also worth noting that brass comes in many different alloys, with many different chemistries. adding silicon makes it harder, and less ductile. adding sulfur and phosphorus the reverse. arsenic affects ductility negatively. obviously, brass for specific firearms applications is tailored by chemistry and resultant mechanical property to individual cases. early browning machine guns would stop when fed regulation 30-06 of the day. they ran reliably on silicon rich hardened brass with different post forming annealing. users of high pressure cartridges in modern sporting guns should take heed, especially in cartridge conversion. never allow the annealing heat time to flow down the sidewall of our cases, as this may weaken them in critical areas.

[Eric Johanen]

I think this has a lot to do with how your rifle is chambered. With a tight match paper patch chamber, annealing the first time is probably not a bad idea. Then check case length and case fit. Anneal and size when called for. With a standard chamber the brass has to be worked to some extent to hold bore sized paper patched bullets and then I anneal after a few years to help avoid work hardening case problems, such as case mouth splits or case wall cracks near the mouth. I don't anneal often but is necessary occasionally. Using standard chambers I use fire formed brass and neck size only. I have lost only a very few cases in 45-70 and this is after many years of use. Mostly mouth cracks and a few splits. Some of my Winchester brass is over 10 years old and still holding up.

[Etienne Brule]

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[BrentD]

Hi,

IMHO,

"Just enough to get a faint red glow in a very dark basement" This is way too hot...

For my part, I use Tempilaq to keep control of the heat on the 0.5 inch near the mouth of the case...

FWIW...

Gerald

No, I don't think is is even close to too hot.

[martinibelgian]

Interesting thread - and as I was looking for a cause for my case stretching with PP bullets in the 45-70 (groove-dia.), all my brass gets annealed after every firing, so I'm tending to think it is too soft... I'll try a few of the other, unannealed lot and check. And maybe better stop annealing for now.

[Etienne Brule]

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[justashooter]

for general purposes, let's talk about what annealing is. every metal can be heat treated, and there are 3 important temperatures for each chemistry family: normalizing, stress relief, and tempering, which can be a wide variety of temperatures (depending on desired effect on mechanical properties) Annealing is another word for tempering designed to reduce hardness and increase ductility, in a practical sense.

when a metal is normalized it is at a temperature below liquidus and yet high enough to free up molecular bonding arrangement, which is naturally ordered by electro-static attraction, based on the natural polarity of molecules. in this state, molecules will aggregate into large "grain" structures. if a metal is brought up to normalizing temps and then quenched (oil, water, air) the molecules will freeze in this large grain structure. large grain structure metal has high abrasion resistance and surface hardness (for the particular chemistry) but low impact resistance, and low ductility (measured by charpy impact and tensioned elongation testing).

if a metal is reheated to annealing temperatures after normalize and quench the grains are loosened just enuf for some of the molecules in them to begin to re-align by natural polarity, and for the larger grains to refine into smaller grains. this causes an increase in grain boundary surface to volume ratio, which increases the differential between tensile and yield strength (reduces brittleness), increases ductility, reduces abrasion resistance and surface hardness, etc.

the trick in designing a heat treating plan is to understand how your particular alloy responds to heat, and to take it through the stages that give you a desired result in mechanical properties. to do this, you have to understand exactly what kind of properties you want.

in our case, we want a brass for continued and repeated use that is dimensionally stable, has "spring" ( a significant differential between tensile and yield strengths), is abrasion resistant, and hard enuf to retain it's shape while being banged around. what we have going against our effort to obtain this magical balance is the fact that while zinc alloying increases brass strength, the increase comes at the cost of the "work hardening" effect that causes split case necks, even when cases are neck sized only, after a certain number of firings. proper annealing can "reset" the work hardening clock, but it should be done at temps and for durations that yield acceptable mechanical properties.

in short, for gun brass, we are looking at 500-650* for inversely proportional durations. this temp on yellow brass looks shiny blue to shiny grey in normal light.

[Etienne Brule]

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[montana_charlie]

Hi,

IMHO,

"Just enough to get a faint red glow in a very dark basement" This is way too hot...

For my part, I use Tempilaq to keep control of the heat on the 0.5 inch near the mouth of the case...

FWIW...

GeraldNo, I don't think is is even close to too hot.
I think it is ... too hot, that is.

AR ammunition comes in .223 Remington, which is always shiny ... and 5.56x45mm, which still bears the coloring from being annealed for the last time in the loading process.
That coloring is 'blue', regardless of country of manufacture.
When you heat brass enough to get any shade of red, the final color is a shade of 'brown'.

[M-Tecs]

What are the benefits of annealing?

1. Better gas seal for low pressure cases.

2. Prevent neck splits.

3. More consistent neck tension. I anneal my 1,000 yard competition brass every time in case using jacketed bullet. For my cast bullet cases I use very little neck tension so I am less concerned the need to anneal.

[country gent]

As stated above annealing is a process of softening and removing memory or spring from cases in our application. Tem isnt the only factor but is soak time at temp and cross section of the material being annealed. Our .008-.010 wall section being annealed requires much less soak time to reach consistant heat thru it than a 1" cube does and a 6" cube needs even more time. Temp remains the same annealing temp but soak times are greatly increased to achieve the same results. I believe most on the thin section of brass were annealing are over annealing by going to the color changes due to the higher temps ( propane tourch flame) and thin cross sections were working with. There are many ways to anneal from machines to hand set ups. All most all cases are annealed in the manufactureing process, probably with an induction heater in line in the dies used. This induction heater heats to a very controlled tem and the time thru it is also consistant due to the presses stroke time. While all brass is annealed most comercial brass has it polished out one exception is lapua. Military brass is normally left visible. At the temps times the manufactureers use there may not be a color change with the annealing either. I anneal in a 10 lb lead pot full of fine Silics sand. Pot is brought up to 700* and cases inserted in the top plates ring of holes. When ounce ring is full to 1 empty hole One case is pulled and quenched another inserted this gives about a 12-15 sec soak time in the hot sand. I get very little color change ( this is also partly because there is no oxegon left present in the sand at that temp) but brass is softer with little spring back. I can maintain consistant temps and time, csases are heated from inside and outside ( unlike the tourch) and It does work for me. When or heat treat had to anneal materials there was charts for size and soak times and temps required. In our case with the thin cross sections a little heat may go a long ways.

[rfd]

i don't see how any annealing is necessary for loading bp in fire formed rifle brass. it's an entirely diff'rent story for any brass that gets work hardening in a press. when i started annealing brass for smokeless rifle cartridges (that required sizing, expanding and seating with crimping), i did the templaq thing to be sure i wasn't over annealing. that didn't last too long, because after a short while, with the right light, most anyone can see the correct color change after only a few seconds or so. it ain't rocket science, imo, but it is an art of sorts.

[Lead pot]

Country Gent.

Silica sand is not a very good conductor of even heat. specially in a lead pot where you just heat the outside edge. I thought that once also to use glass beads from my sand blaster for this use. But I forgot that you can hold a glass rod and melt the end of the rod and slide your fingers from the back of this rod to the melted end and you will be very close before you burn your fingers. :) Learned this in elementary school :)

I don't think it really matters when you anneal the case if you get a red glow. I have seen red case mouths when I did it and in a short time after a few uses they are hard again.

[Etienne Brule]

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[Etienne Brule]

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[BrentD]

You guys way over think this. There is a place for snnealing, but surely not every time it is reloaded.

I've shot my best scores and won the most matches with Starline that had never been annealed.

After annealing, it didn't do any worse but it sure wasn't any better.

[Etienne Brule]

" I've shot my best scores and won the most matches with Starline that had never been annealed. "

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