Stuck Case in Chamber

K

kilotanker22

New member
So I might have goofed up a little.

Loading for 300 PRC in a Browning X-Bolt rifle. Hornady brass, annealed after every firing. Load that I have used for a couple weeks now (30+ firings) and to this point have had no sign of trouble with.

Last weekend I was shooting and one of the pieces of brass gave me a hard bolt lift and did not want to extract. As the bolt cammed open, the extractor slipped off of the rim of the case. I was a little horrified at first, cause this has never happened to me before. Well, needless to say mt range trip was done for the day.

I got home and put a cleaning rod down the bore and gave it a rap with a hammer and the case popped right out. I was surprised it took so little to dislodge the case. Anyway, I set about trying to figure out why this happened. I could have just started load development over again, but I feel it is important to investigate when things do not turn out as planned.. This way, maybe I can prevent myself from making the same mistake in the future.

I measured the case and to my surprised it was .001" longer than usual when coming out of the chamber. I figured this could maybe explain the heavy bolt lift. I set about measuring the ammunition that I had not fired yet, and imagine my surprise when they are already at the length that most cases come out of the chamber after being fired.

I assumed the the lock ring on my die was not tight enough. The die had adjusted itself at some point. Presumably when I was installing or removing the die from the press. Before adjusting anything I decided to review my notes. I was appalled that I had written the incorrect number down when I recorded the cartridge base to datum measurement. In this case I knew what the correct measurement was, but I had recorded it incorrectly.

I have since loaded a few test rounds with the appropriate dimensions to test this afternoon.

My question is, Have any of you experienced this? Can annealed brass fail to contract enough to extract a case if the dimensions are too big and it does not expand enough to begin with?
 
Annealing after each firing sounds a little excessive, but since only the neck is involved, I doubt that caused your problem. How many times have you loaded that case? Is your load at or near max? It is possible to get a case a little over expanded near the base, to the point that the sizing die doesn't quite get it where it needs to be. The camming force of the bolt will load it, but the grip of the extractor may be insufficient for a tight case. As you noted, it wasn't all that tight, just a little much for the extractor. Measure your case diameter near the base. I don't think 1 mil too long would cause your problem.
 
Too much mystery for a definite answer. By "annealing" what is your process?
Are you just annealing the neck via a controlled process?
You certainly dont want to anneal the case body or head.

I appreciate your attention to the sized length of your case,but I can't get my head around how that would stick the case in the chamber and extraction failure.

Describe your annealing process. An over annealed case could be the problem.

Too high of pressure could be the problem. Are you loading hot? You mentioned hard bolt lift. That often indicates high pressure. Consider something like an overcharge could have made that particular round high pressure.


Might you have dropped that round and picked up some range grit?

You said something about 30 loads. Do you mean you loaded 30 rounds,or you loaded that case 30 times?

Are you checking your trim length? A neck that is too long cannot release the bullet. That could be your problem.Its been hot out lately. Did that cartridge get heated in the sun or a hot chamber?

Do the paper clip test for stretch rings.

And check your bolt face/extractor. Wear? Gunk?
 
HiBC said:
Too much mystery for a definite answer. By "annealing" what is your process?
Are you just annealing the neck via a controlled process?
You certainly dont want to anneal the case body or head.

I appreciate your attention to the sized length of your case,but I can't get my head around how that would stick the case in the chamber and extraction failure.

Describe your annealing process. An over annealed case could be the problem.

Too high of pressure could be the problem. Are you loading hot? You mentioned hard bolt lift. That often indicates high pressure. Consider something like an overcharge could have made that particular round high pressure.


Might you have dropped that round and picked up some range grit?

You said something about 30 loads. Do you mean you loaded 30 rounds,or you loaded that case 30 times?

Are you checking your trim length? A neck that is too long cannot release the bullet. That could be your problem.Its been hot out lately. Did that cartridge get heated in the sun or a hot chamber?

Do the paper clip test for stretch rings.

And check your bolt face/extractor. Wear? Gunk?
Click to expand...
Cases are trimmed. I trim them to 2.575". Max case length is 2.580".

Neck and shoulder area are all that is annealed. Dark room with a drill and torch until I see a dull red color. When finished, I can hold the base with my bare fingers without getting burnt. They are hot to the touch but not so hot I can't hold onto them

When I say 30 firings, I mean I have fired 30 rounds of that exact load, with no issue. Started with factory ammo, and have loaded each of these cases 3 more times. So this would have been the fifth firing on this case.

No flattening of primer, no ejector marks or swipes, primer pocket is still tight after five firings.

I believe the brass did not spring back enough after firing due to it being soft, and the fact that it did not really have room to expand enough for the brass to spring back. The brass not springing back could account for the hard bolt lift on only that piece of brass.

Temperature was 10 degrees cooler than when I first tested the load. Barrel was warm but not hot. The case that stuck was only the sixth shot of the day and I don't let them sit in the barrel for.long before squeezing the trigger.

No other signs of pressure on this case. Also worth noting is the velocity of this shot was within the standard deviation from the average velocity.

I am curious to know how one over anneals a case neck. It would stand to reason that soft is soft. In fact I believe that heating the neck just enough, will cause more variation in bullet grip, than if you had heated slightly more than enough. I will admit that it is possible that the shoulder was annealed about the same as the neck. Which I do before I sized the cases. I do this to allow the neck and shoulder to work harden as I manipulate the dimensions of the case.

In this instance, I was not actually pushing the shoulder back at all during the sizing operation. This leads.me to believe that the shoulder was three things.

1: still soft due to not being pushed back and work hardened after annealing.

2: Being that they were not pushed back, the case did not expand enough to work harden the shoulder area and cause the case to spring back.

3: Since the case did not spring back after firing, the case was firmly held against the bolt face, causing my hard bolt lift. Also, the case not springing back in the shoulder area, caused it to stick in the chamber. This is evidenced by a scuff marks at the case shoulder junction. Presumably from the steel chamber when I forced the case out of the chamber.
 
I have given the rifle a good cleaning and loaded some more ammunition with the appropriate dimensions. If my theory is correct, I should have no trouble
 
Another note is that this load is .030" away from contact with the lands. So the shoulder being a couple thousandths forward would not cause the bullet to contact the lands.
 
So you only have .005 of wiggle room on your trim length ? That’s “cutting” a little close , add .002 or .003 shoulder bump when sizing and you could only be .002 from the mouth jamming into the leade/throat . Not saying that’s the issue but it stands out to me as a possibility. What is the trim to length ?

EDIT , just looked up the trim to length , Hornady says 2.565 so you’re “starting” .010 longer then you should . Are you trimming after sizing every time ?
 
Metal god said:
So you only have .005 of wiggle room on your trim length ? That’s “cutting” a little close , add .002 or .003 shoulder bump when sizing and you could only be .002 from the mouth jamming into the leade/throat . Not saying that’s the issue but it stands out to me as a possibility. What is the trim to length ?

EDIT , just looked up the trim to length , Hornady says 2.565 so you’re “starting” .010 longer then you should . Are you trimming after sizing every time ?
Click to expand...
Yes, I anneal, trim, chamfer and deburr after every single firing. Trimming takes place after sizing to prevent some cases from being longer. Every single case is 2.575" exactly
 
Although, after getting the sizer die set right, I had to adjust my trimmer as it indexes off of the shoulder. I use the WFT 2 case trimmer from Little Crow Gunworks.
 
LOAD: You don't say where you were, but all indicators are you went over pressure.
Either the load or a mistake on the fill.

Annealing: Going by color is the worst way to determine you have annealed. Very likely you no longer are in the optimal range (over). Its not going to hurt as long as its the neck but the advantage of a precision case is gone.
While I use color check, its a cross check with other methods including a temple stick check as well as post follow up that the color change polishes off (no polish off its over done but as you do it each time you won't be able to tell. You could take a sample and do a long polish.
While bench rest shooters sometimes anneal after each firing, we are talking people who shoot 1/10 MOA area. Experimenting I have found about once ever 8 round works so I do it once every 5 rounds and bias to a bit under full anneal.

Case Trim: .001 is not going to jam the case. There is no need to control the trim that tightly but it not going to hurt. There is latitude for over max as that is not absolute X to not cross.
As long as the trim is close and consistent, you can trim more off.
 
RC20 said:
LOAD: You don't say where you were, but all indicators are you went over pressure.
Either the load or a mistake on the fill.

Annealing: Going by color is the worst way to determine you have annealed. Very likely you no longer are in the optimal range (over). Its not going to hurt as long as its the neck but the advantage of a precision case is gone.
While I use color check, its a cross check with other methods including a temple stick check as well as post follow up that the color change polishes off (no polish off its over done but as you do it each time you won't be able to tell. You could take a sample and do a long polish.
While bench rest shooters sometimes anneal after each firing, we are talking people who shoot 1/10 MOA area. Experimenting I have found about once ever 8 round works so I do it once every 5 rounds and bias to a bit under full anneal.

Case Trim: .001 is not going to jam the case. There is no need to control the trim that tightly but it not going to hurt. There is latitude for over max as that is not absolute X to not cross.
As long as the trim is close and consistent, you can trim more off.
Click to expand...
The reason I left the cases longer and trim every time was to leave a little more case neck to grip the bullet. Probably doesn't make much difference, bit I don't r really see how it could hurt.
 
Also, people keep telling me not to over anneal the neck, but no one ever explains to me at what temperature the brass is over done and precisely why. Obviously if you get the metal hot enough to begin melting is not good, but someone pleas explain what happens to brass when over annealed, what property of brass causes this and why.

Edit:
I certainly do understand the risks if too much of the case is annealed too closely to the base, and I make sure this is not happening.
 
Ah, CMU metallurgist here. Far below the melting point you will experience grain growth. Yes, metal is not a continuum, but an agglomeration of crystals. Once grain growth occurs, your metal is permanently softened. What you want to do in annealing is relieve the stress of work hardening without initiating grain growth. Typical case annealing technique should accomplish this, but leave it hot too long, and your case is ruined.
 
According to Amp Annealing, Zinc cannot burnout of the brass unless it is brought to it's boiling point, or if there are specific chemicals present. You can find their research on their site.

It is my understanding that even after grain structure has began, the brass itself does not lose the ability to be cold worked and hardened. Not this type of brass at least. Only the neck and shoulder are annealed with the neck taking most of the heat. I can hold cases in my hand without gloves after just a few seconds. I am fairly certain I am not over heating them.

Also I anneal prior to sizing. When the die reduces the diameter of the neck and shoulder, then the expander opens the diameter of the neck back up, This will begin to work harden the necks after the annealing.

If brass can get too hot to ever be work hardened again, then how is it we can melt a lot of brass, pour into ingots, then beat them with a hammer to harden them? If cartridge brass can lose the ability to harden without coming to the melting point, then why can brass be melted, cast and hardened.

Grain growth can occur with heat, but the work hardening will reduce the size of the grain structure as well.
 
At what temperature is brass ruined and loses its ability to be hardened? This type of brass, UNS C26000, specifically. Nearly all cartridge brass is made from this alloy.
 
ligonierbill said:
Ah, CMU metallurgist here. Far below the melting point you will experience grain growth. Yes, metal is not a continuum, but an agglomeration of crystals. Once grain growth occurs, your metal is permanently softened. What you want to do in annealing is relieve the stress of work hardening without initiating grain growth. Typical case annealing technique should accomplish this, but leave it hot too long, and your case is ruined.
Click to expand...
At what temperature is brass ruined and loses its ability to be hardened? This type of brass, UNS C26000, specifically. Nearly all cartridge brass is made from this alloy.

Why is the brass ruined after a certain temperature and what property of brass causes this?
 
Boy howdy, I touched a nerve. Yep, if you melt down the brass, cast an ingot, roll sheet, and deep draw cases, properties will be restored. Otherwise, leave it too long at temperature, and you're had. But that isn't why you stuck a case. You stuck a case because you loaded too much powder. Measure the base, and your problem will be revealed.
 
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Just asked you to explain a question. How hot is too hot? Between what temperature range does this alloy lose all of its mechanical properties to the point that work hardening ceases to exist? I am genuinely curious about that question. Especially with plenty of my own anecdotal experience. Groups have tightened considerably, seating depth is more consistent, case life has improved. Aside from my own ignorance, I have no reason to believe that I have been overheating cases. All the circumstantial evidence I have would suggest otherwise.

If my stuck case was caused by the powder charge, it would stand to reason that I should be able to reproduce that result. If it was caused by the way I sized the case, then sizing them correctly will show a difference.
I did take your advice and measured just ahead of the head at the bottom of the case body. I measured brand new Hornady factory ammo and got .530", I measured my sized cases and also got .530", my fired cases were .531" with a few ten thousandths of variation.
 
Although, I must concede that I do think that your prediction is possible. I also measured the case that stuck, and although it was the largest that I measured, it was only .0005" larger in diameter than the rest of them.
 
Kilo i never had 1 stick in the chamber but i had them give me a harder bolt lift. I was bumping the back .002-.003. I turned my die down to just kiss the shell holder. The problem went away. This is on 15 times fires 6.5 prc cases. If your just bumping the shoulder back your die may not be sizing the base enough.
 
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