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Bushmaster Super Member
Joined: Jun 12, 2005 Posts: 11390 Location: Ava, Missouri
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Posted: Mon Jan 04, 2010 4:51 pm Post subject: Re: Any suggestions for why this case failed? |
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Elvis...It is entirely possible that the sports shop set the shoulder back too far also...
_________________ I have one nerve left and yer standin' on it...
DEMOCRACY Two wolves and one sheep voting on what to have for lunch...
LIBERTY A well armed sheep contesting the outcome of the vote... |
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gelandangan Super Member
Joined: May 07, 2006 Posts: 6396 Location: Sydney Australia
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Posted: Mon Jan 04, 2010 4:56 pm Post subject: Re: Any suggestions for why this case failed? |
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You can fix headspace issue in a rolling block by ring lining the face of the chamber or a shim on the breech.
A good gunsmith should be able to silver solder a shim onto the face of the chamber or breech.
Mind you, there is a lot of butchers out there posing as gunsmiths that may
damage your chamber or breech by overheating it while silver soldering thus render the gun unsafe to fire.
_________________ A straight line is the shortest distance between two points.
A smile is the shortest distance between two people.
Do - Not try!
gelandangan.weebly.com/ |
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Mon Jan 04, 2010 4:56 pm Post subject: Re: Any suggestions for why this case failed? |
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Keep the ideas coming!
When I get the broken brass out, I still don't think I'll use the Winchester brass. Looks like my only other choices are Starline and Remington. I need to avoid nickle plated. Starline is so much more inexpensive than Remington, I'm aprehensive about using it.
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fnuser Super Member
Joined: Dec 23, 2008 Posts: 914 Location: S.W. Missouri, U.S.A.
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Posted: Mon Jan 04, 2010 5:04 pm Post subject: Re: Any suggestions for why this case failed? |
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crush a lead pellet between the block and the rim depression of the chamber it should be close to .070" the (headspace of a 45-70) if it is much bigger then you have excessive head space, another cure instead of shimming is setting the barrel back. if its not say under .072" then it was probably just a bad case.
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Mon Jan 04, 2010 5:39 pm Post subject: Re: Any suggestions for why this case failed? |
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I checked the four cases I shot before this one. I don't know the order I shot them in but the primers are proud (moved out of the pocket) the following amount: .004, .010, .012, .015. Makes me think the cases were progressively sticking to the sides of the chamber more and more until the case fractured instead of the primer moving (its flush on the broken case).
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Bushmaster Super Member
Joined: Jun 12, 2005 Posts: 11390 Location: Ava, Missouri
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Posted: Mon Jan 04, 2010 6:35 pm Post subject: Re: Any suggestions for why this case failed? |
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Make sure you know and understand the progression of combustion in the case and chamber...
1. Firing pin strikes the primer and shoves the case forward in the chamber.
2. Combustion takes place pushing the primer out the amount of the head
space. Case expands and grips the chamber.
3. As the pressure starts to drop the case is slammed back against the
breach face reseating the primer.
If the head space is excessive the case can seperate (as your photo shows) between #'s 2 & 3...
_________________ I have one nerve left and yer standin' on it...
DEMOCRACY Two wolves and one sheep voting on what to have for lunch...
LIBERTY A well armed sheep contesting the outcome of the vote... |
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Pumpkinslinger Super Member
Joined: Sep 22, 2007 Posts: 5001 Location: NC foothills
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Posted: Mon Jan 04, 2010 6:40 pm Post subject: Re: Any suggestions for why this case failed? |
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I think Fnuser has an excellent idea! The headspacing is about the only thing I can think of that would cause a case to separate like that. I've got a repro rolling block (Pedersoli) and I'll try Fnuser's method if I get a chance soon just to see what I get.
_________________ Mike
"I ain't no better than anybody else, and there ain't nobody better than me!" Ma Kettle |
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Elvis Super Member
Joined: Jul 27, 2008 Posts: 9239 Location: south island New Zealand
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Posted: Mon Jan 04, 2010 7:48 pm Post subject: Re: Any suggestions for why this case failed? |
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yes bushy you could be correct. I only partial resize and have no issues.the idea of putting a no go gauge in and trying to force the bolt shut to see if chamber is correct size didnt impress me much either.hopefully this case is just a bad case [pun intended]
_________________ You shot it You pluck it !
Them who eats the most duck eats the most feathers! |
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Mon Jan 04, 2010 8:13 pm Post subject: Re: Any suggestions for why this case failed? |
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I don't have any lead around but I did put just a short case head in an used a feeler gauage. Case rim was .063. At first I was getting some close tolerance with only .007 fitting. Then I started to look for ways to ensure I had all the slack taken up. When I dropped the hammer, the case went in further. Now I get a .014 in behind the case base and I can jam in .018.
I had a RB Gunsmith check it out. He said it was a bit loose but should shoot ok if I indexed the brass. Maybe this gab is too much or Aloysius' idea of the o-ring will work well enough.
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Mon Jan 04, 2010 8:16 pm Post subject: Re: Any suggestions for why this case failed? |
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Pumpkinslinger wrote: |
I've got a repro rolling block (Pedersoli) and I'll try Fnuser's method if I get a chance soon just to see what I get. |
I've seen the new Pedersoli rifles and they are much tigher than mine. Interested in what you measured.
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1895ss Super Member
Joined: Jul 21, 2005 Posts: 2612 Location: Not Here...!!
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Posted: Mon Jan 04, 2010 11:40 pm Post subject: Re: Any suggestions for why this case failed? |
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Aloysius wrote: |
Slimjim, on the South Africa forum they give advice for the Lee Enfield to put a small O-ring on the rim before you use that brass for the first time. This way you push the cartridge to the bolt.
And afterwards you just necksize and don't need the O-ring anymore.
The minute I did understand why and how, I also understood I'm still not too old to learn.
What works on a .303 British could also be helpfull for a .45 Government? |
The 45-70 is not a bottle neck case, it is a straight wall case there is no shoulder, it head spaces on the rim. Bushy's idea of a brass drift may be better then a wooden drift and I would sure try one or the other or both.
slimjim, I would bet if you switch to Remington brass you may get rid of your problem, cause it will handle more pressure then the WW brass and it is much better quality and or you may have to fix that headspace problem.
_________________ A cruel truth is much more desirable than a really nice lie.
'Tis far better to walk alone than to follow a crowd or an a**hole going the wrong way. |
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PaulS Super Member
Joined: Feb 18, 2006 Posts: 4330 Location: South-Eastern Washington - the State
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Posted: Mon Jan 04, 2010 11:49 pm Post subject: Re: Any suggestions for why this case failed? |
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Brass is supposed to be elastic enough to expand to the case diameter and then spring back about .0005 to 0015" releasing its hold on the chamber.
If the remains of the case is still that tight to the wall of the chamber then the brass had pressure on it that exceeded its elastic limit.
To me, that means over pressure - whether you were at the highest listed load or not. I have run into this with my 357 Maximum - and had no more problems after reducing the load 5%.
_________________ Paul
__________________
Speer, Lyman, Hodgdon, Sierra, and Hornady = reliable loading data
So and So's pages on the internet = NOT reliable loading data
Always check data against manuals
NEVER exceed maximum listed loads |
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1895ss Super Member
Joined: Jul 21, 2005 Posts: 2612 Location: Not Here...!!
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Posted: Mon Jan 04, 2010 11:52 pm Post subject: Re: Any suggestions for why this case failed? |
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PaulS wrote: |
Brass is supposed to be elastic enough to expand to the case diameter and then spring back about .0005 to 0015" releasing its hold on the chamber.
If the remains of the case is still that tight to the wall of the chamber then the brass had pressure on it that exceeded its elastic limit.
To me, that means over pressure - whether you were at the highest listed load or not. I have run into this with my 357 Maximum - and had no more problems after reducing the load 5%. |
I agree ......... but we are talking here about Winchester brass in a 45-70.................. If you don't start the bullet perfectly straight, when seating bullets, you end up with a bulge in the side of the case, this doesn't happen with Remington brass because it is a bit thicker and much stronger. 45-70 WW brass is very soft it seems.
_________________ A cruel truth is much more desirable than a really nice lie.
'Tis far better to walk alone than to follow a crowd or an a**hole going the wrong way. |
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fnuser Super Member
Joined: Dec 23, 2008 Posts: 914 Location: S.W. Missouri, U.S.A.
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Posted: Tue Jan 05, 2010 8:14 am Post subject: Re: Any suggestions for why this case failed? |
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14 + 63 = 77 that could be out of spec.
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Bushmaster Super Member
Joined: Jun 12, 2005 Posts: 11390 Location: Ava, Missouri
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Posted: Tue Jan 05, 2010 8:24 am Post subject: Re: Any suggestions for why this case failed? |
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That's my view too fnuser. It looks like the case is seperating at the point where the case is starting to get thicker. The thinner part expanding against the chamber and the thicker part blowing back against the breech face. Hence, seperation...
_________________ I have one nerve left and yer standin' on it...
DEMOCRACY Two wolves and one sheep voting on what to have for lunch...
LIBERTY A well armed sheep contesting the outcome of the vote... |
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