Crazy never seen anything like this before
- Thread starter williepete
- Start date
I thought about that but I use tempilaq to check temp
and it is on the money
The most baffling thing to me is
a firer formed case is 1.4165
after it is resized it is 1.4135 after it is loaded and sits overnight
it grows to 1.4185 that is longer than the firer formed brass
how doe that happen.
and it is on the money
The most baffling thing to me is
a firer formed case is 1.4165
after it is resized it is 1.4135 after it is loaded and sits overnight
it grows to 1.4185 that is longer than the firer formed brass
how doe that happen.
DLT
Silver $$ Contributor
I have pulled this move before so it can happen. Make sure once you measure your bump, if you remove the comparator to measure anything else zero your calipers. Then once you reinstall the comparator be sure to zero calipers again. Not saying wm that’s what happened but I did it once and put my butt in a spin for a day trying to figure what happened
I hear ya I have done that before also
now I always check the zero
Back tracking and looking at what I might have done differently
I am leaning towards the annealing
the reason is that I usually watch every case that goes through the annealing process I usually anneal 50 cases at a time so it is no biggie for me.
This time I did not do that I was setting up a new intellidropper and was focused on that
if the annealer got bumped moving the torch that could of throwed off the whole process.
causing the extreme spring back
I am use to seeing 000.5 spring back when properly annealed
but 5k is over the top
it has been soo long since I have not annealed that I don't remember what kind of spring back that I had before i started annealing
I will start from scratch and re anneal the cases in question and see what happens
thank you for your and everyone else also
much appreciated.
If you are using 750 F Tempilaq to confirm temperature you are not annealing the brass.
DLT
Silver $$ Contributor
Do you let the case have some dwell time in the sizing die for a few seconds before lowering the ram ?
Perhaps you have formed a donut in some of the cases, and when you seat a bullet past the donut, it expands out the neck enough, but only at the very bottom, that your measurement tool catches on the slightly expanded neck-shoulder junction? And the measurement is funky because it's such a small amount of brass sticking out?
DirtySteve
Gold $$ Contributor
Any pictures of the cases/loaded rounds?
A puzzle & learning opportunity.
That the issue occurs with time (overnight), and on it's own, tells me it's brass spring back. The brass going to the lowest energy level it can, over time. Here also, the shoulder is seemingly going beyond where it ever was.
It's like there is energy added that initially springs back to provide desired HS, but spring back continues overnight -to a place it must have been before. After all, why would it go to 1.4185 if it hasn't been there, or even further out to ~1.419 at some point? Shoulders in themselves do not spring back so much, and no brass goes to where it hasn't been by itself.
It's even longer than fire formed by 2thou, so your chamber (your best die) is never putting the shoulders there. So it must be your FL sizing doing it.
For HS offending cases, what is the case OAL doing?
That the issue occurs with time (overnight), and on it's own, tells me it's brass spring back. The brass going to the lowest energy level it can, over time. Here also, the shoulder is seemingly going beyond where it ever was.
It's like there is energy added that initially springs back to provide desired HS, but spring back continues overnight -to a place it must have been before. After all, why would it go to 1.4185 if it hasn't been there, or even further out to ~1.419 at some point? Shoulders in themselves do not spring back so much, and no brass goes to where it hasn't been by itself.
It's even longer than fire formed by 2thou, so your chamber (your best die) is never putting the shoulders there. So it must be your FL sizing doing it.
For HS offending cases, what is the case OAL doing?
A puzzle & learning opportunity for sure!
I thank you for posting your thoughts on this it got my wheels turning,
in your post when you said After all, why would it go to 1.4185 if it hasn't been there,
got me thinking and going through my old reloading logs revealed that the brass has been there before.
This brass at one time was used in a different barrel that was removed because of poor performance and replaced with the new match barrel that is on it now.
That along with my annealing process which was wrong as stated by watsupdoc which opened up my eyes to that, I will now go to the dark room glow method and use it to anneal the brass. so thanks to you and whatsupdoc I think we may have solved my problem.
Thanks to everyone for their input and comments.
Good things can happen when people talk and work through things together.
I modified my sizing technique and as a result have much more consistent shoulder bump. I run the brass up into the die, let it dwell a couple seconds, lower it just enough to grab the base of the case (most of brass is still up in the die), rotate 60 - 90 degrees, and run it back up into the die, allowing it to dwell again a couple seconds at TDC.
This has eliminated springback for me. I should add that I also switched from Hornady One Shot to Royal Case Lube. Brass that goes into the die real easy is reformed much more consistently.
This has eliminated springback for me. I should add that I also switched from Hornady One Shot to Royal Case Lube. Brass that goes into the die real easy is reformed much more consistently.
You still have a reality that shoulders alone cannot spring back that much.
I suspect that your FL die is over sizing, lengthening cases, and then reforming them back down.
That it's adding energy to a significant length of the case body in this process, and this length is whats equalizing overnight (not the shoulders).
Just a theory,, not trying to jinx your plan.
If that brass was shot in a different chamber with increased headspace it would make sense that those handful of cases are experiencing memory that cannot recover despite annealing.
Some thoughts..
I'm curious which tool you are using to measure shoulder position?
I load 223 as well. With a .330" comparator bushing, my cases measure ~1.458" from head to shoulder datum. Max that will fit in the rifle (Tikka Varmint) is 1.461".
For you to be getting ~1.416-1.418" you must be using a larger diameter bushing.. maybe .350"?
I am under the impression that the best place to measure the shoulder is at a point midway between body and neck diameter. Unless I'm mistaken, Hornady says to use the .330 bushing for 223 Rem.
I don't think that's causing this problem, but it's something I noticed.
I also anneal at every firing, using a flame in a dark room. I've never used Tempilac, I spin the case and heat it til the neck turns a dark dull red.
The heat affected zone extends into the shoulder, because I've found that annealed brass is very consistent in how much the shoulder gets pushed back, plus the colour change extends into the shoulder.
There's enough of a difference between annealed and not-annealed cases that I have to change the die setting to get the same shoulder measurement if I don't anneal.
I've never had the shoulder move after sizing, at least not enough that the rounds won't chamber.
Your "after sizing" measurement might be closer to a no-go situation than you think.
I never go by what size the brass is when it comes out of the gun, that varies enough to be unreliable. Rather, I "stretch" a piece of fired brass by deliberately not pushing the shoulder back until I get a case that won't chamber smoothly. Then I measure that case and bump the shoulder back until it does chamber with slight resistance. That becomes my "max" dimension. Then I adjust the die to produce brass that's 2 thou shorter at the shoulder for reliable operation.
This is with a bolt rifle. You'll want more than 2 thou bump in a semi-auto, or so I'm told. Maybe 3-5 thou?
As for the brass being worn out causing this, I have my doubts. I'm up over 20 firings on many of my Lapua 223 cases. The usual failure mode on my Lapua cases has been incipient case head separation, but more towards the middle of the case rather than at the web/body junction. Primer pockets stay tight with reasonable pressure loads.
I will say that the Lapua brass is prone to donuts at the bottom of the neck if it's full length sized regularly. If you're getting donuts you'll feel a slight "bump" or "step" in the seating pressure as the bullet bearing surface passes the base of the neck and enters the body of the case. In a tight chamber, that neck expansion might be enough that the round won't fully chamber without extra effort. It can also cause pressure to spike because the case can't expand at the donut to allow the bullet to release easily.
I'm curious which tool you are using to measure shoulder position?
I load 223 as well. With a .330" comparator bushing, my cases measure ~1.458" from head to shoulder datum. Max that will fit in the rifle (Tikka Varmint) is 1.461".
For you to be getting ~1.416-1.418" you must be using a larger diameter bushing.. maybe .350"?
I am under the impression that the best place to measure the shoulder is at a point midway between body and neck diameter. Unless I'm mistaken, Hornady says to use the .330 bushing for 223 Rem.
I don't think that's causing this problem, but it's something I noticed.
I also anneal at every firing, using a flame in a dark room. I've never used Tempilac, I spin the case and heat it til the neck turns a dark dull red.
The heat affected zone extends into the shoulder, because I've found that annealed brass is very consistent in how much the shoulder gets pushed back, plus the colour change extends into the shoulder.
There's enough of a difference between annealed and not-annealed cases that I have to change the die setting to get the same shoulder measurement if I don't anneal.
I've never had the shoulder move after sizing, at least not enough that the rounds won't chamber.
Your "after sizing" measurement might be closer to a no-go situation than you think.
I never go by what size the brass is when it comes out of the gun, that varies enough to be unreliable. Rather, I "stretch" a piece of fired brass by deliberately not pushing the shoulder back until I get a case that won't chamber smoothly. Then I measure that case and bump the shoulder back until it does chamber with slight resistance. That becomes my "max" dimension. Then I adjust the die to produce brass that's 2 thou shorter at the shoulder for reliable operation.
This is with a bolt rifle. You'll want more than 2 thou bump in a semi-auto, or so I'm told. Maybe 3-5 thou?
As for the brass being worn out causing this, I have my doubts. I'm up over 20 firings on many of my Lapua 223 cases. The usual failure mode on my Lapua cases has been incipient case head separation, but more towards the middle of the case rather than at the web/body junction. Primer pockets stay tight with reasonable pressure loads.
I will say that the Lapua brass is prone to donuts at the bottom of the neck if it's full length sized regularly. If you're getting donuts you'll feel a slight "bump" or "step" in the seating pressure as the bullet bearing surface passes the base of the neck and enters the body of the case. In a tight chamber, that neck expansion might be enough that the round won't fully chamber without extra effort. It can also cause pressure to spike because the case can't expand at the donut to allow the bullet to release easily.
He's using the Short Action Customs comparator insert. The reason his measurement is less than the Hornady gauge is because the SAC gauge is cut to match the shoulder/chamber angle so it indexes off the actual shoulder, not the datum line.
It's nice because the case fits in the insert like a glove, I much prefer the SAC comparator over the Hornady. But as you mentioned, that doesn't have anything to do with his issue...both gauges accomplish the same objective.
cdgaydos said: Perhaps the bullet expanding the neck while seated transferred force to the shoulder… outward force on the diagonal shoulder translates to pushing the shoulder forward…
The shoulder is not moving. What is happening is the resized case is so close to the chamber size that the bullet seating is causing the necks to enlarge(normal) but the enlargement right where the neck meets the shoulder causes the shoulder to now be larger right at the junction; imitating a longer shoulder measurement, preventing the case from chambering. Adjust for an extra thou of shoulder setback and it fill probably take care of the problem.
How are you testing the "won't chamber" ? Most AR's will resize/move a shoulder a thou or more when the bolt slams shut, or seat a bullet deeper if it hits the lands.
Frank
The shoulder is not moving. What is happening is the resized case is so close to the chamber size that the bullet seating is causing the necks to enlarge(normal) but the enlargement right where the neck meets the shoulder causes the shoulder to now be larger right at the junction; imitating a longer shoulder measurement, preventing the case from chambering. Adjust for an extra thou of shoulder setback and it fill probably take care of the problem.
How are you testing the "won't chamber" ? Most AR's will resize/move a shoulder a thou or more when the bolt slams shut, or seat a bullet deeper if it hits the lands.
Frank
How are you annealing? If they are not annealed enough, they may have more spring back variation? Are the necks and maybe part of the shoulder getting red when you anneal? A controversial area is what happens if you anneal, let it air cool then anneal again. Some people say it has no effect. I think I would try it. Never had a problem like this in 50 years of reloading. You have to see red when annealing to at least try to get past the point of just stress relieving and not annealing.
Added later: Just read your using Temp-Lac. Temp-Lac was never intended to be used with an 1800F flame on it. 750F for a fraction of a second is not hot enough to anneal. It's a made up garbage number. At 750F you may be just getting a partial stress relief?
From the website Aurubis.com
Each line is a different starting hardness. 400C is 752F.
Check out the Erik Cortina video on annealing. All of Erik's video's and Jack Neary's are interesting.
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I will agree with Frank. An AR bolt going home should be able the chamber that no problem.
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