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Long story short. I got some handloads (I didn’t fire any and they have been disassembled). After inspecting the fired cases I noticed the shoulders and necks where severely split. What is the likely cause? I did find corrosion inside the unfired rounds and the fired rounds weren’t fired in the rifle intended for the load.
The brass is corroded and/or brittle with age. Some old brass is perfectly usable after annealing to deal with the brittleness of age. Some old brass is corroded due to bad storage so much so that it is unsafe to fire and if fired, splits at the shoulder and the neck or in the body of the case.
Greetings Magnetite,
I had some Federal cases crack just like that. The cases were range pick up, I think once fired. About half the cases cracked just like that first time which is unusual as my experience cracks usually develop in the middle of the neck. The survivors were neck annealed with a candle and have and have given no more trouble neck sized in the same chamber. The cases were in one spot on the range and I assume they came from the same rifle. I wondered if they had been fired in a military semi auto which often have different chambers but really don't know. There was no sign of corrosion.
Regards Grandpamac.
Normal in my 270 wsm after a few reloads
I think that combined with the points made by others that there is also something going on with the way the cases have been sized. They haven't got a nice crisp clean shoulder like they should. Sort of looks like they have been neck sized leaving a donut then at a later date had a real 'crunch too far' full length size
Thanks for all the help. MOA Hunter I think you might be on to something. Here’s a picture of the unfired cases. I think the left are virgin cases and the right are once fired.
The ones on the right are once fired and then full length sized / prepped cases ? is that correct. Which if loaded as they are then turn into the side ventilated type first shown ? What is the difference in shoulder diameter between left and right ?
Can someone who knows more about this than me step in here please as I am guessing / hunching
To have any hope of a Diagnosis ' more information is needed . Rifle / age /actual load . for a case to fail what happens is that it is forced to work beyond its acceptable limit . This can be a brass or even rifle problem , but the answer will be found by measuring the rifle ( not as easy as it sounds ) or by measuring the brass pre and post firing .
Giving the Rifle a real good clean ( chamber area ) is a good start and then measure cases including thickness of the brass . I had a split case problem with a FR8 , I solved it by using Milsurp brass because it is thicker . And PLEASE do not buy into the ridiculous practice of annealing things with candles ,that is the preserve of monkeys .:wtfsmilie:
The ones on the right look like they were sized deeply and with unannealed brass they do a lot of effort on firing to the chamber.Quote:
Originally Posted by Magnetite
I did some measurements (probably not the ones needed).
There were two different weight projectiles which appeared to be: 139gr and 140gr Norma Vulkans. The 139gr was loaded with 45.5gr of an unknown extruded powder, and the 140gr with 45.0gr of what looks to be the same powder.
I measured the cases with a headspace gauge:
Undamaged fired case: 1.768"
Split cases: 1.766", 1.767" x2, 1.753"
Virgin cases: 1.761" x3
Resized cases: 1.740" x3, 1.776"
The loads are approximately 25 years old and were made for a military surplus Carl Gustaf. The shoulders split when fired in a Ruger 77 Mark II.
Ook please pass me that bananaQuote:
Originally Posted by Tankd
Attachment 153322
There's more than one issue here.. hard to tell if those marks in the sidewalls are the start of case head separation or marks from the chamber or dies.. the damage on the rims look like extractor gouging from sticky cases or from the shell holder from stuck cases due to lack of propper lube in the dies.
Check the inside of case where that ring is for a groove..
Hard brittle cases or over work hardend/sized will case all this especially if they are sized outside of a few thou head space tolerance
I had that happen to nearly 50 out of a bandolier of 50 wartime mk7 .303 headstamped GB or something, someone at the range told me that was a UK manufacturer. The particular SMLE implicated was my one with the most generous/excess (a matter of viewpoint) shoulder space. Anyway those two planets, "Brittle" and "Stretchy" aligned for split shoulders and necks to occur.
That said, the bullets all flew nicely downrange as intended apart from frequent clickbangs, and the brass was Berdan primed anyway, so as long as no case separations it was just another day at the range... (-:
Would the trick be to fire a couple of new factory rounds and post a picture here of the cases for comparison ?
I checked for case head separation and couldn't find any. The marks in the middle line up with the container they were stored in. As for the marks on the rims, they are from a shell holder in an inertia puller.Quote:
Originally Posted by Wingman
So far I'm guessing it's a combination of the shoulder being pushed back too far and the cases becoming brittle with age.
I'll see if I can find some factory cases from the rifle.Quote:
Originally Posted by Moa Hunter
Please read and understand Recovery Annealing https://www.ampannealing.com/about-brass-hardness/ .Quote:
Originally Posted by Marty Henry
Metallurgists discuss annealing as involving recovery, recrystallization and grain growth stages. In the recovery stage hardness remains relatively constant as some of the original properties of the brass recover,
Most likely your previous reloader has just reloaded the cases to their max. times and age has done the rest with storage being a factor .
Greetings Magnetite,Quote:
Originally Posted by Magnetite
I think I have spotted something in your measurements that may explain the neck splits. The fired case measures 1.768 inches compared to a new case at 1.761 inches giving about .007 inches of head space. This is generous but not unknown with factory chambers. Most of the full length (?) sized cases measure 1.740 inches. This gives .028 inches of headspace grossly excessive by any measure. This means that the base of the neck is worked excessively each time they are sized. I think that the handloader may have known there are problems and tried to partial size a case, the one measuring 1.776 inches. I doubt if this case will chamber. So to my eyes the principal problem is the dies which are grossly oversizing the cases. This is more common with continental military cases and my own 6.5 x 55 mm dies produce .008 inches of excess head space. I set the die off the shell holder to fix the problem. You have nailed the source of the marks on the case bodies as your storage boxes as suggested elsewhere.
As far as candle annealing case necks. There is a tendency by some to regard the latest kit as mandatory for good handloading and regard anyone who persists with older methods as a Neanderthal or worse. There is some science behind candle annealing provided the correct technique is used as written up by John Barsness in Handloader mag. I have been using it for about 3 years and have had excellent results. I will try to do a post on it in the future.
Regards Grandpamac.
You do not measure cases to determine Head space , you use these https://www.brownells.com/gunsmith-t...uges/index.htm .Quote:
Originally Posted by Magnetite
Military chambered rifles are generally use bigger dimensions than civilian rifles.
Milsurp cases are generally thicker .So you tend to use lower powder weights.
Here on pg42 you will find 6.5x55 case dimensions https://saami.wpengine.com/wp-conten...sting-Copy.pdf
First resized case is on the small size .
Basically your cases are of unknown age / stored for a long time in unknown conditions / Used in a Milsurp chamber / Used how many times ??. Candidates for the bin , they are worn out.
Even if the cases are old etc chucking them wont cure the problem of the dies being incorrectly set or not matching the chamber. At this point we are not sure which it is.Quote:
Originally Posted by Tankd
