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Old December 3, 2012, 02:41 PM   #1
hounddawg
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Inspect those cases boys and girls

A week or two back I was shooting my .204 practicing technique and on the last round of my third group when I ejected the case had split cleanly in two about a 3/4 or an inch back from the neck. Nothing catastrophic or even mildly alarming occurred thankfully. In fact I was not aware there had been a malfunction until I ejected and was holding 2 pieces of case. The only obvious sign that there had been a issue was the bullet went about a half a MOA to the left. I did pack up that rifle immediately of course and when I got home gave it a good inspection, however I put examining the other 35 rounds until this morning.

Now to be honest I have gotten real casual about my case inspections. I have a nice lighted magnifier for that purpose but had just gotten lazy. I have just been giving them a quick once over with the Mark 1 Mod 0 eyeball instead of doing the full monty. This morning I went over those cases with the magnifier and found 9 more out of the 35 that had almost a imperceptible white line running partially around the case just about where that other one had split. You cant feel it even with a dental pick from the inside or the outside, it is just a faint line where the brass is a shade lighter.

Anyway just thought I would post this to remind others not to be lazy like I was. I guess it could have been worse this time ther ewwas no damage to the shooter or the gun. I suppose I was real lucky in that half the case could have been stuck in the throat of the barrel which would have least been a pain and possibly could have ruined a hunting trip
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Old December 3, 2012, 03:17 PM   #2
243winxb
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Case separation from pushing the shoulder back to far on FL sizing is the cause.

Last edited by 243winxb; December 3, 2012 at 03:24 PM. Reason: add my photo.
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Old December 3, 2012, 03:58 PM   #3
Brian Pfleuger
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Interesting, the description and photo are both indicating case failure much closer to the neck, farther from the head, than I have previously seen described. The typical area I hear referenced is only about 1/4" above extractor groove.

That picture looks a lot like what my Lee Deburring tool does to cases.






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Old December 3, 2012, 04:02 PM   #4
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That is really a wierd place for a case to seperate. In my experience it has always been much lower near the base of the case (which is usually due to improper resizing on my part).
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Old December 3, 2012, 04:44 PM   #5
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Quote:
Originally Posted by OP
... I was shooting my .204 practicing technique ....when I ejected the case had split cleanly in two about a 3/4 or an inch back from the neck.
Quote:
Originally Posted by Homesick
...really a wierd place for a case to seperate
By any chance were these less-than-full-up loads?
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Old December 3, 2012, 07:03 PM   #6
hounddawg
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Quote:
Case separation from pushing the shoulder back to far on FL sizing is the cause.
that's it but in my gun it is because I have the head space a bit too tight so same thing

Quote:
By any chance were these less-than-full-up loads?
39 gr Sierra on 24.5 grains of RL10 3700 FPS factory OAL. Not a full case but within a half inch

went back through a tin of my fired cases and culled about 10 more. Pulling the barrel and resetting it tomorrow
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Old December 3, 2012, 08:24 PM   #7
243winxb
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Not from a Lee tool, but can look the same. Here was the cause of my separations. Ammo loaded in the late 80's without the use of a comparitor or case gage. Each station of the shell plate was a different thickness. If the FL die was set using the station in the photo, some brass would separate on firing. Nothing in the instructions with the loader back then. Now they tell you to use a case gage.
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Old December 3, 2012, 08:32 PM   #8
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went back and dug some out of the trash and measured where the light ring was and could find no real consistency. Some were almost in the middle, some were a bit closer to the case mouth but all were closer to the neck than to the base. Most looked like the ones in Brian's photos except I don't use a Lee deburring tool, at least never on those cases. I might be being overcautious here but 204 brass is fairly cheap. Anyway, head space is reset no more guns or bullets tonight, time for a adult beverage
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Old December 3, 2012, 09:27 PM   #9
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Quote:
...39 gr Sierra on 24.5 grains of RL10 3700 FPS factory OAL.
I looked at Lyman's 49th for a reference and got 40grV-Max/23.3gr RL-10 at 56,000psi.

Alliant didn't list RL-10 for the 204, and Sierra didn't have anything for me in their 5th ed either. So I went looking on the web... found loads as high as 25.1gr under a 39gr BlitzKing

But then, I ran QuickLoad at your 24.5gr under a the 39gr Sierra and got 66,000 psi. (The Case max is 58.7).
Any chance you're stressing things a bit?
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Old December 3, 2012, 09:55 PM   #10
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never seen any pressure signs yet, went up to 25 gr doing load testing with no pressure signs. Just dropped back to 24.5 becasue that load give me the best groups ( .2 center to center 5 shots) out of any gun I own. 243winxb nailed it , I knew that I had the head space too tight from bolt closure giving a smidgen too much resistance, just been lazy about resetting it

I will keep that in mind though and if I have another issue drop back to around 21.5 grains and do a workup from there to see if I can find another sweet spot. For that matter I will give those cases and primers a real good exam when I go to the range this week. Don't have any here that have not been cleaned and resized.Started thinking about you post and while that is a heavy barrel gun it is also 26 inches long so I am probably pusking a K or 2 better than what you came up with. BTW I got that load from this page

http://www.rugerhunting.com/204_data_alliant.php
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Old December 3, 2012, 10:16 PM   #11
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QuickLoad has a couple of default assumptions that I've found to be a bit pessimistic for the .204. If I change those setting to match what I've seen in real life, it thinks that load is about 54,000 psi and just over 3,700fps from a 24" barrel.
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Old December 3, 2012, 10:27 PM   #12
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Lost my chrono data for that load but if memory serves correct (doubtful) I was hitting right at 3800. Anyway when I reset the headspace it was too tight on the go gage, so I think that should cure any problems and if another piece of this Hornady goes south on me I will trash em all and work up a new load for those Winchesters still in the bag
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Old December 3, 2012, 10:33 PM   #13
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My little girl stole the computer for a moment there, I was estimating the speed.

It says 54,484fps at 3,784fps.
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Old December 3, 2012, 11:08 PM   #14
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Brian, what have you set up differently here to lower the pressure but keep the speed ?

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Old December 3, 2012, 11:19 PM   #15
Brian Pfleuger
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Case capacity tends to be closer to 33.00gr and the default weighting factor makes no sense. The .204 is a lot closer to being over-bore than it is straight-walled. I have found that a weighting factor of between 0.42 and 0.45 is most accurate.
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Old December 4, 2012, 09:14 AM   #16
243winxb
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Quote:
243winxb nailed it , I knew that I had the head space too tight from bolt closure giving a smidgen too much resistance, just been lazy about resetting it
NO, My problem came from to much slop as the cartridge sits in the chamber. SAAMI calls it Head Clearance. If your having trouble closing the bolt you can not have my problem. Something else is causing the hard closure. Possibly an expanded web area from over pressure?
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Old December 4, 2012, 09:53 AM   #17
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ok my bad on interpreting your previous post then. I thought you were stating that the stress caused by moving the shoulder back to far was weakening the case metal. Now I know my head space was definitely on the short side, last eve I put the go gage in and felt more than normal resistance which I corrected. After resetting the headspace it closes with no resistance on the go gage, but 2 pieces of scotch tape on the end and it would have to be forced. Could a short head space cause a weakening of the case metal in the middle of the case ?

For what it matters my neck sized cases are 1.838, SAMMI specs are 1.840. I reload to a COAL of 2.260 which for my barrel is .080 off the lands. A bit of a jump but it works so I have not messed with it. I don't own a case comparator but I guess I should. I just did a full resize on the new cases then and since use a Forster neck size die

Oh and on the powder load here is a link to a Sierra reload data page where it shows up to 25.1 grain loads of RL10 is a safe load using a 26 inch barrel. SInce I did my load workup I have never used more than 24.5 grains + or - 0. All loads are trickled to weight to a scale double checked against a beam balance

http://www.rugerhunting.com/204_Ruger_sierra.pdf
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Old December 4, 2012, 01:06 PM   #18
243winxb
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If your neck sizing, the brass should not be separating from stretching. Now i dont know what is the cause?
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Old December 4, 2012, 02:44 PM   #19
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The only thing I can think of is that the cases are separating at the juncture of where annealing stops and stiffer brass starts -- i.e., a materials/stress transition point.

Normally I'd expect the effect to be graduated down the case body. But maybe not. (I could envision induction heating as producing such a sharp transition).

Is there a possibility of your annealing a dozen cases/extended shoulders "the traditional way", and then tracking their failure rate compared to the others?
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Old December 4, 2012, 03:25 PM   #20
hounddawg
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@ Win243xb

I still am of the opinion that the short head space was acting like your resizing die and bumped the shoulder too far back on the initial chambering and some cases had to be resized with the full length die becasue I have my neck tension set very low on my neck sizing die and keep a full length die with the decapping pin broke to do a emergency neck sizing when loading . I just dump the powder out anfd do a quick full length resize if the bullet seemed to be a bit too loose

@mchavey

these cases have not been re annealed. I bought 100 Hornady cases plus 2 boxes of loaded Hornady (for break in) when I built the gun and half are now on their 3rd & half on the 4th firing
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Old December 4, 2012, 05:59 PM   #21
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Quote:
....these cases have not been re annealed.
You want to try re-annealing half and then seeing if that changes the tendancy to separate ?
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Old December 4, 2012, 06:02 PM   #22
243winxb
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Pulling the barrel and resetting it tomorrow

hounddawg, If the rifles chamber is headspaced at 1.5713" maximum & the brass is sized to the minimum of 1.5575" this gives head to datum slop of .0138"
Brass will separate using these SAAMI measurements. Be careful how you headspace that barrel. http://www.saami.org/PubResources/CC...04%20Ruger.pdf I am not a gunsmith, i hope you are.
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Old December 4, 2012, 06:50 PM   #23
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not a gunsmith per say but I was a manual machinist for 5 years and then a millwright for about 30 more. I am using a Manson go gage for setting the barrel, the bolt closes easily now with it in place, take the go gage and put a .002 aluminum shim on the back and bolt will no longer close

http://www.brownells.com/aspx/learn/...aspx?lid=10511

when I set that barrel the gage was on back order and I used a piece of Hornady factory ammo to set it. I will not ever make that mistake again. I have a feeling factory ammo is set up a tad on the short side to make sure it chambers in all guns.

BTW your post did give me pause for thought and I just rechecked it for the 4th or 5th time and am satisfied with it
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Old December 4, 2012, 06:51 PM   #24
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Out of curiosity, why couldn't the OP simply size to whatever dimension just allows the bolt to close,
and quit worrying about that aspect of the problem.

Then re-anneal....
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Old December 4, 2012, 07:08 PM   #25
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just did another interesting experiment. Took a piece of previously fired and unsized brass from that gun and it took .005 worth of shims to reach a no go condition. Then I took a piece of new Winchester brass that has been fully resized and did the same thing with the same results. Yet using the head space gage it is set correctly

My head is starting to hurt now.

Well at least know the head space is now correct. Go gage and the bolt close with slight resistance at the botton. .001 shim and bolt will not fully close .002 shim and bolt will not close at all

If I get another case separation or see anymore light rings on those cases I will pull the powder and bullets from whatever is left unfired and recycle them all
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