45/70 Split Case Mystery Solved

[CW4USARET]

I spoke with my local gun smith about the horizontal split in a 45/70 case mentioned in another post. He surmised that there was a small air pocket between the fiber wad and the base of the lead bullet and the chamber of the Henry was not as tight as that of the Sharps which then allowed for excessive expansion of the brass in that specific area. I had fired 10 rounds thru the Henry and 3 of the 10 showed of failure or impending failure of the cases at the exact location on each case.

I guess you learn something every day.

jrf

 

[Jimbo357mag]

I wonder if what you learned is true. A little air space in a cartridge has never caused a case split as far as I know but a large chamber or hard brass will.

 

[Rick Courtright]

I wonder if what you learned is true. A little air space in a cartridge has never caused a case split as far as I know but a large chamber or hard brass will.

Hi,

Jimbo, I'm thinking the fiber wad/lead bullet part of the story is important: upon ignition, there will be a momentary pressure wave between the two, much like what goes down the barrel later. From shotgun experience where a wad stuck in the barrel can cause a banana peel, I can imagine the same thing happening in miniature inside the case. Just a theory, of course!

Rick C

 

[Jimbo357mag]

Jimbo, I'm thinking the fiber wad/lead bullet part of the story is important: ...

I suppose the wad might have something to do with it. To test that theory the OP should shoot some of the same rounds and brass without the wad and see what happens.

 

[woodperson]

Why is there a fiber wad "in there"?

 

[CW4USARET]

The paper wad is there to protect the base of the lead bullet according to the SPG BP Cartridge Reloading Primer and the Blackhorn 209 Metalic Cartridge Load Guide. Hatchers Notes also mentions the black powder explosive reaction and it's affect on a bullet as compared with smokeless powder burn and pressure affect on a bullet.

jrf

 

[Jimbo357mag]

I think I miss-spoke about air space in a 'black powder' cartridge. I had forgotten you were talking about BP. I think we all know that there should be no air space in BP cartridges. Are you saying that the tiny air space created by the wad is what caused the problem? I can understand that now. Please excuse my doubts. Seems perfectly reasonable now.

 

[DGW1949]

As noted, black powder (a true explosive) behaves differently than smokeless powder (duh). To my recollection, the rule of thumb when using PB in conjunction with a straight walled case was always to load to the base of the bullet (or to the base of a firmly compressed fiber top wad) in order to eliminate "dead air" space.
Not sure how well that would work in a bottle necked case.
In more recent years, I've seen other mediums being used to top-off a reduced load of BP, with the appropriate amount of (uncooked) grits being the most popular in CAS/SASS circles...again, the point being to eliminate air space.

As for a proper load of BP "damaging the base of a lead bullet" to any meaningful extent, I've never seen or heard of such a thing, and would purty-much have to see it to believe it.
Sounds more like trying to pick nat sh*t outa pepper to me...

But hey, I guess some folks has more time on their hands than me.

DGW

 

[Shaggy357]

Did you full length size the case? Carbide die? Long straight wall cases have a tendency to get the "Coke bottle" effect when full length sizing. Hold one up and look at the case. See a )( kind of look? Load with black powder, add a wad, then seat the bullet, and when you crimp, I will surmise that more likely than not, you can see the wad and the base of the bullet in the case wall. Mark it with a sharpie. See if that is where it cracks.

On my straight wall cases, I usually only size enough of the case to hold the bullet. My brass is shot in the same gun every time. Once in a great while...4-5 reloads later...I have to run my 357 Max, 30 Carbine, etc through the full length sizer as they want to grow a little too much near the case head. Sometimes a little harder extraction is not enough to warrant the full length resize. (HINT) If you pre-check your brass fit in your chamber after setting up the sizing die, you will know right away if the case will fit. If brass fits the chamber, and bullet will seat in the case, you should be good to go.

Some more ideas to mush around in the gray matter.

Steve

 

[Psb1911]

Did you full length size the case? Carbide die? Long straight wall cases have a tendency to get the "Coke bottle" effect when full length sizing. Hold one up and look at the case. See a )( kind of look? Load with black powder, add a wad, then seat the bullet, and when you crimp, I will surmise that more likely than not, you can see the wad and the base of the bullet in the case wall. Mark it with a sharpie. See if that is where it cracks.

On my straight wall cases, I usually only size enough of the case to hold the bullet. My brass is shot in the same gun every time. Once in a great while...4-5 reloads later...I have to run my 357 Max, 30 Carbine, etc through the full length sizer as they want to grow a little too much near the case head. Sometimes a little harder extraction is not enough to warrant the full length resize. (HINT) If you pre-check your brass fit in your chamber after setting up the sizing die, you will know right away if the case will fit. If brass fits the chamber, and bullet will seat in the case, you should be good to go.

Some more ideas to mush around in the gray matter.
No "Carbide" re-sizing die in 45/70!
Steve