45-120 Case Cracks/Separation

[mehavey]

I've had a (Farmingdale) Shiloh Sharps 45-3¼ since `81; and over years of sporadic shooting have experienced several unexpected case separations about an inch above the head. All of these loads are Black Powder (GoEx 1Fg and/or Swiss 1½), and with both RCBS and HDS (Huntingdon) cases.

Today another case (HDS) case separated, and I can see still another loaded case that has all the signs of getting ready to go on next firing: (Bright ring partially marked w/ blue sharpie)

Anyone else experienced this with long BP loads/cases such as this 3¼ ?
(I've had none w/ four other 45-70's and two 45-90s -- just this cartridge/rifle)

 

[J.G. Terry]

Head Separation:

Head Separation: I had some 2 7/8" cases fail very much like yours. The these splits were bad enough to leave the front part of the case in the chamber. I could not tell if the separation came from poor brass of poor maintenance by the previous owner. My solution was to replace the old brass with Starline cases from Buffalo Arms. The mixed Bell and Others were retired. No problems since. My rifle is a C.Sharps.

 

[4V50 Gary]

I'm wondering about the chamber. Shiny or is there a line?

Have you tried annealing the brass?

 

[Scorch]

Have you tried annealing the brass?

This.

 

[Catman42]

i assume that your cases are very very clean? if not when loaded this will happen. also please explain proper annealing as i ruined some cases once by making them too soft. their has to be a answer by some member, i dont have it except cases not completely clean.

 

[T. O'Heir]

"...proper annealing..." It's unusual to anneal case bodies as you need to quench but in most cases the annealer(that's you) heats the brass too hot. Red hot is too hot. You heat with a plain propane torch until the brass changes colour and quench in plain tap water.
That inch seems like a long way from the rim. How many times have those cases been loaded? The rifle's headspace OK?
The loads out of a manual? There's supposed to be 45-120-3 1/4 data in the Lyman Reloading Manual 49th Edition.

 

[mehavey]

OK... after much mucking around with a zillion variations that went not only nowhere, but killed three more cases (10-thou stretch&worse every shot), I went back to simplified assembly from 35 years ago:

- Annealed necks using 750 Tempilaq
- Cleaned/sonic'd/walnuted the cases
- Trimmed to 3.25" perxactly
- Used Lyman BlkPwdrGold* Lube cut as a 0.2"-thick/quartered disk as grease cookie
- Sandwich the cookie between 2 0.060" veg cards hand-pressed home
- put a "release" 0.030 card above cookie sandwich
- Shoot cases Unsized
- Hand-insert bullet: just enough friction w/ paper patch to retain
- Kicker duplex charge of 10gr 4759
- Enougth GoEX 1Fg to result in an UNcompressed charge column giving me ~⅓" shank depth (~89-90gr -- 152 volume setting on the Harrells)
- Wiped 1x-&-out Damp Patch, followed w/ 1x-&-out dry between shots . . .

* Only use I've found in the 15 years I've happened to have the tube of it -- normally use DLG in the grooved&Lubed game

 

[4V50 Gary]

headspace on a rimmed cartridge is off the rim. What is peculiar is how the case is consistently thinning at the same place; which is why I asked about the chamber.

 

[mehavey]

It has cracked cases before -- about 3/4" from the mouth 35 years ago.

It was then that I literally stumbled on the earliest variation of the load combination above and everything snapped together all at once. BUT ... the way I was having to load it then was a PITA -- so I put it away -- Only to come back and try classically-simple/single-powder/no-cookie/single-card/Grooved-&-Lubed....

................ what part of "NO" had I failed to understand four decades ago?

Chamber is fine, as evidenced by spottiness/mirror case-wall surface in the above load/No-Stretch cases upon examination. There's also no paperclip test "feel" in the ones that are showing signs of going, Obviously a "distributed" thinning mechanism. Weird.

New loading technique is now fairly straight-forward/fast/simple for the equivalent load column/new materials/cookie installation..
I might start loading for it again




postscript: Primer-Only/Headspace does have primer backing ever-so-perceptively out ~0.002". But the Load above apparently negates that with case/chamber dynamics that result in net zero stretch.

 

[Dufus]

Try waxing the cases with Imperial. Nothing to lose.

 

[mehavey]

`Tried that (actually lubed the cases). No go.
It appears the stretching was coming from the powder/load column stretching the case from the inside as it was shoved forward/out.
-- even w/ squeaky-clean/sonic'd/walnuted cases.

 

[J.G. Terry]

Single Shot Rifle Journal

There is a short article in the recent Single Shot Rifle Journal. This article describes the stretching problem and methods for removing stuck parts of the cartridge case from the chamber.

 

[mehavey]

I'll try to track down that SSRJ article
Meanwhile, back at the ranch . . .

Got my new TOY in the mail today.
Loaded a case w/ the 4759/1Fg combo above topped w/ a 60-thou card by hand.
Stuffed some Lyman's BlkPwdrGold into the New Toy; extruded a 0.2"x½" ribbon onto the the kitchen counter; used the loaded case to cut a grease cookie;** pushed another 60+30thou card down on top; and seated the bullet (and by hand)

Took it out late 6 tonight drizzle/fog/failing light, front post as sight....
First/Clean/Cold/...Only... shot overlaid on yesterday's target:

Leave it alone.....




** (really nifty)

 

[Dufus]

I'll bet that nearly shocked the pants off of you. AND, almost in the dark to boot.

 

[mehavey]

Black powder, twilight darkness, high humidity and light fog.... talk about lighting up the night.