45-90 split cases

[Keith]

Still experimenting.
Having done this with Wano 2F OK, I thought I would try Wano 3F.
Filled 5 brand new Starline cases with 100 grns topped with a card wad, to fireform the cases by breechseating my Baco PP slick.
Touched off the first, it hit the paper. The next two did not and split the cases. I gave it away then and emptied the rest.
Never had this happen before, any ideas?

[Gunlaker]

I posted an answer to your post on the Shiloh forum. I think if you keep away from the FFFg when breech seating you'll be much happier. Several years ago Steve Garbe wrote an article about case stretching/separation when breech seting with black powder.Lots of people will tell you to look for head space, or that you had the chamber wet, etc. That is not going to be the problem. Breech seating is much more likely to separate a case than shooting fixed ammunition with bp. It's the powder grabbing the case as it moves forward. Chris.

[Keith]

Thats all I can think of as well. The chamber was dry and the card wad was just inside the mouth so powder grabbing is all thats left.
I have used 3F in the 38-55 breech seating to good effect but I guess powder capacity must come into it as well.

Keith

[flatsguide]

Total noobie here so cut me a bit of slack. How much compression on the powder did you use? My thought is that a lot off compression may make case separation easier as the compression load is higher along the side walls of the case and this side load decreases as it goes towards the head of the case. Is Over annealed Star brass the possible cause? Just thinking out load.
Richard

[BrentD]

I don't think compression matters and I certainly don't think it could cause that.

Did you size these cases before loading them?

[Lead pot]

I just did the same thing a couple days ago with the new .44-75 ballard cases cut down from .45-2.6 Starline brass and pulled two apart at the same point where yours did, but mine were seated in the case 1/8" and I used 2F KIK powder compressed about 1/10" The first shot I lost a case and I put the fault on not cleaning the oil out of the chamber and bore like I normally do. I just plain forgot to do it. the second case pulled apart on the third shot. It was cold out about 6 degrees so I used the blow tube and the humidity was around 80% so a lot of moisture went through the tube and some must have leaked into the chamber.
When I got home I cleaned the cases and took measurements where they pulled apart with knife edge of the calibers into both ends of the case and they measured .0047" and .005" case walls where they separated. Pretty thin.
I breach seat the Sharps .44-100 St using a full case of 3F OE powder with .120" compression with a flush card and no lube and I haven't had separation with that load.
When ever I have cases pull it is usually when I wipe the bore followed with a mop and when the mop gets damp the case stretches.
Breach seated bottle necked cases with out a lube wad I had 7 out of 10 cases pull off. Something that never happens when I have a lube wad in the case.


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[EDG]

This is an often reported phenomenon with black powder. I say that because I have shot lots of smokeless BP equivalent loads since 1971 and I have never seen nor heard of a tube shoot off with smokeless.

You can carry this even further. I shot skeet pretty seriously for a decade. A lot of those shotgun shells were reloaded with every possible mishmash of wads and hulls. A shot shell wad column gets collapsed and crushed by the powder combustion pressure. The gas seal edge of the shot cup is expanded and drags on the case tube which can be very cheap and rough plastic. It is rare to see a tube shoot off unless a reloader uses an old hull until it is about to fall apart.

I have also seen high speed photos of a black powder charge emerging from a BPCR barrel and the powder looks like it is still a compressed burning clod.
I think it is just the hard sharp edged grains of black powder that grab the case walls and pull them off. Use a gun with a wet chamber and it is worse. Leave lube on your brass and it will probably do that too. I do know that none of that causes the cases to pull apart with smokeless. I have very lightly lubed a lot of cases the first time they are fired when fire forming cases for an obsolete bottle neck or wildcat round. I have never had a case stretch. They actually get shorter by .004 to .007.

[John Boy]

Never had this happen before, any ideas? Put a slight bell on the case mouths so they go up against the base of the breech seated bullet. This reduces the amount of gases that leak into the chamber with an opening between the case and the bullet

[montana_charlie]

If I were to try breech seating, I would set the depth of the bullet so that it reliably held the case head firmly against the face of the breechblock.
Otherwise, it would be necessary that the case rims were thick enough to fill the rim recess, ensuring the same casehead/breechface condition.

[Lead pot]

A lot of the problem is the lack of standards with these black powder rifles. This creates a problem for the brass manufactures to hold the rim thickness. I have rifles that have a rim recess from .065" to .078". Pedersoli has one recess depth, Shiloh has theirs and C-Sharps they seem like all have their depth as well as the head diameters variances as well as the case mouth diameters. The .40-70 or the .44-90bn's for instance those rim thicknesses are all over the place.
The only way you can reduce a chance for a headspace variance is having a tight fitting bullet into the throat and let the breach block finish seating the round so the case head is tight on the block and the firing pin cant push the case farther into the chamber creating a head space problem.
This might not be the problem with Keith's separation problem and I know what caused my separation, oil in the chamber I forgot to clean out before shooting the first round and moisture form the blow tube. Looking at Keith's cases the way the carbon blow back stuck to the annealed cases. My cases look like that when I have a wet chamber making the carbon stick like that. You can see the distance the heat traveled on his clean unfired case.
But all of this is speculation. Failure in the brass, powder, moisture, breach seating, head space who knows maybe it's all of the above. It happens now and then.

[BrentD]

Just one time this happened to me, and it happened with nearly every cartridge in the batch and in two rifles (until we finally stopped shooting and pulled the rest of them). Eventually, I narrowed it down to being sizing lube that I could not feel on my fingers but had not been sufficiently removed from the cases. I would expect the same thing in this instance.

[Lead pot]

Sizing lube is a good one I forgot to mention. I just sized down 800 .45-2.6 cases to .44-2.5 for the .44-75. But I run them through the wet tumbler to wash off the lube before I load them. I make up my own sizing and swage lube that just wont wipe off with a rag. It's a mix of Castor oil and Lanolin with a little STP. The first time I used it I was digging brass out od the bore :)

[Keith]

I don't think compression matters and I certainly don't think it could cause that.

Did you size these cases before loading them?
Unsized new cases. Not annealed either.
Just recently I tried it again with fireformed cases and FF Swiss without a problem.
The load of FFF in the first post was not compressed either. I am now making sure I have a dry chamber before loading. Something I learned here and had not been fussy with earlier.
Thanks for the replies.

Keith

[BrentD]

If they were new, perhaps they were lubed and sized and then not washed at the factory?

I think something was on those cases. I really don't believe it was the powder, but like many things, we will never really know for sure.

[RPRNY]

Put a slight bell on the case mouths so they go up against the base of the breech seated bullet. This reduces the amount of gases that leak into the chamber with an opening between the case and the bullet

Second this excellent advice. Ned Roberts, in his excellent articles on breech seating in black powder Scheutzen rifles mentions this very technique. Creates a sort of reverse gas seal to encourage pushing the case head back against the breech.

Also suggest fire forming your brass at a lesser charge - like 65 - 70 grains topped by wax/lube "bullets", to address chamber variations. I don't like 3F in large capacity cartridges but can't say that's a contributing factor.

[BRUCE MOULDS]

breech seating serves 2 purposes well.
the first is it is a good way to fireform cases when no dies ere available.
do this and use the right bullet and you might never need dies unless you use bottleneck cases and need to bump the shoulders.
the second purpose is to maximize results at the target.
this requires lengthening the airgap between the top of the case/wad on case full of powder until the best groups appear.
in 40 and 45 cal this will happen at about a 1/8" gap.
these 2 things can be done at the same time.
if you have a rim recess so large that it is causing case separations, incorrect breech seating is not the answer.
the answer is to measure the thickness of your rims, select the 3 cases with the thickest rims, and send them with the gun to a competent gunsmith.
this is always wise when rebarreling.
too much variation in rim thicknesses might require all brass going to the gunsmith for rim thickness uniforming.
with bottlenecks a die can be used when forming brass to get good headspace on the shoulder.
if you must use a bullet to hold the case head against the block, fixed ammo is the way, using hard bullets.
powder must be compressed at least 1/10" to support the bullet when chambering.
keep safe,
bruce.

[johnson1942]

were the case one hundred percent clean on the inside when loaded to shoot? a slightly dirty case will split like that as the powder grips the side and stretches them too much, been there, done that many many years ago and learned to clean my cases as new each time. never happened again. just a thought.