Lucky day?

Likely Hornady lists the load because they tried it hundreds and hundreds of times and it worked fine.

Back 50 years ago, the big scary powder was 4831 in light loads. A friend and I didn't know this, ran 160 rounds of a terribly-light load of 4831 through a Kar-43 with no troubles at all. I will NOT give the exact load, but we were using a cast bullet for a .32-40 because that was the only mould we had. Worked fine. We used a bunch of the same stuff in a lovely little Kar. 88 without troubles, too. Likely the PRIMER was starting the bullet down the bore, so pressures were super-light; thunderous report and immense fireball at the muzzle seems to have confirmed this. Likely what helped us was the cast bullet (cast because we could not afford jacketed bullets at $5 a hundred). I would NOT want to try that same load with a jacketed bullet, not knowing what I know now.

Ball powders are strange things. I understand the manufacturing process fairly well and it is impressive. The part which mystifies me is taking a bunch of chemical which really WANTS to burn at speeds very close to detonation...... and SLOWING IT DOWN CONSISTENTLY AND SAFELY so that it can be used in a wonderful variety of loads in a bewildering array of calibres. When you think on it that way, the Winchester engineers have really accomplished miracles. Untold tens of billions of rounds of ammo have been loaded with Ball Powders and used successfully, much the same as with 4831 (originally a cannon powder) and the safety record is awesome.

But we have to remember that the W-W Carcano ammo produced by Winchester for the US Government was loaded with Ball powder and it had an INCREDIBLE fireball and report when fired in a Shorty. Obviously, much of the charge was burning in the AIR rather than in the Barrel. This is the "white box" ammo which was labelled as Lots 6000 through 6004; a lot of it was sold here and in the USA in the '60s. It is what LHO had, by the way.

And we cannot forget that unburned Flame Retardant chemical from Ball powder was what very nearly ruined the M-16 and led to it being called "Jammin' Jenny" in Viet Nam.

And now we have what appears to be a completely-anomalous case of a strong rifle disintegrating with a light charge of the stuff.

The secondary-explosion theory appears to account for this latest incident.

No reason to condemn the powder, just the same as no reason to condemn 4831 50 years ago: it is just TOO DARNED GOOD even to think about condemning the stuff. But perhaps we should be a bit more careful in its application. Clearly, the lessons of the 1960s have been forgotten; I have even read articles pooh-poohing the whole idea....... but those wrecked rifles remain.

Odd thing is that the chemical composition of most Ball powders is similar to that of Ballistite, with which the original Carcano ammo was loaded. Both are nitrocellulose powders with nitroglycerine added to bring them to desired performance. What is different is the RATE OF BURN. Flake Ballistite was very fast; they used only 30.9 grains of it with a 163-grain bullet of .266" diameter (TBSA - 1909) and they got 2395 ft/sec in a 30.75-inch barrel: very respectable performance.

But W-760 is very slow, even though it is a highly-energetic powder.

And the SHAPE is very different, Ballistite being in flakes with a large amount of surface area for the mass: very easy to ignite, versus Ball's spherical shape, most possible mass for area of ignition, plus retardant coating, making it even more difficult to ignite.

I think the thing to do with this highly-energetic but slow powder is exactly what Winchester says to do with it: use it in heavy loads in large casings. In THIS role, W-760 has proved itself a thundering success ever since it was introduced.

The light loads, especially in Shorties, I think we should leave to quick-igniting powders more suited to light loads.

It's just too bad this had to happen. It was a nice little rifle.

GOOD part is that the Operator is safe: a testament to the great STRENGTH of this much-derided little rifle.
 
Manufacturers test their bullets/powder/loads to give an indication to the reloader of what is appropriate. However, these loads were found safe IN THEIR RIFLES OR PRESSIRE BARREL. Since they have no control over what another person does, or the condition of any other rifle except their own rifle, there is usually a disclaimer printed in their manuals.

A person who reloads, especially for the odd or older calibres, should ALWAYS consult more than one Manual or Source. I always consult at least THREE when working up a load for a new rifle or calibre. I also LOOK AT WHAT RIFLE THEY MANUFACTURER USED. This is quite apparent in older manuals where the 6.5x55 Swedish Mauser loads were worked up in a Carbine barrel of less than 18 inches long.

The INTERNET is one of the WORST sources of information. I have seen very dangerous load information printed, and just because one guy was lucky enough to get away with it, it does not mean that it can be taken as the Gospel Truth that it is a safe load. There were many published reports in Gun magazines way back in the late 1950s and 1960s, (PRE-INTERNET), of Mosin-Nagant rifles that were chambered to 30-06 blowing up, but lately there are a few people on the Internet Forums who figure that the Mosin-Nagant is safe to rechamber to 300 Winchester Magnum, and they will argue loudly about it.

I always remind beginning reloaders that there is 50,000 pounds of pressure six inches in front of their nose. Older rifles do suffer from older technology and fatigue over the years and we really do not know just how much a Military rifle has been fired or the conditions it served in. Quality of weapons deteriorated during a War, especially for the side that was losing. Eye and hearing protection are a MUST when shooting.
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Thanks smellie and buffdog for your responses. I do have a question. Could it be possible that the bore could have been rough enough with that very long bullet to cause the overpressure?
Not enough to not let the bullet exit but enough to create pressure. Not sure if possible just a thought.

I did slug after it happened .268". I had scrubbed the bore with a brush, went after the copper and carbon separate, then wipeout multiple times. The bore was grey, rifling was good. Nothing that many of my other rifles don't have.
 
I have a couple more pics as well, one is another pic of the stock with the magwell back in showing the crack more.

The other is what I dug out of my wound on my nose last night. I thought it was the extractor that had cut me. I've been digging ball powder out of my face and thought I had some in the cut. Took a bit to get it out, ended up being a piece of the case.




 
I had a "wierd" experience with a military rifle with a rough bore years ago. The rifle was a M96 Swede and the bore was definitely not in good shape. Some pitting and well worn. I had a very accurate mid range jacketed load I shot regularly(several hundred) in a couple M38's

I fired 5 rounds for accuracy at 100yds. The first 2 were fine. #3 the bolt was a little sticky on extraction. #4 a little more so. Being 20 yrs younger and much more foolish then I think I am now I fired the 5th round. Had to pound the bolt open with a piece of wood. Primer was completely flattened and cratered around firing pin mark. Really "weird" thing was the group was around an inch BUT one of the holes had a spiral rooster tail of lead spray around it on the paper . Load was just above starting loads in most manuals. Powder was 4064. Bullet was Hornady .264 140gr SP

I never fired the rifle again and traded it off to a dealer after explaining to him what had happened. Still have the target somewhere. I've always thought the bore condition had something to do with it. Why pressures seemed to increase with each shot I have no idea. William Shatner would say "Wierd or What"


Old Ranger
 
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Re: Post 43.

I don't think it was a rough bore that did this to you, friend.

With a charge of a slow powder as light as what you were using, there should have been no problem with a pressure build-up from a bullet being stripped. IF a bullet had been stripped, you would expect the Jacket material to remain, at least in part, in the bore and the remainder of the bullet being expelled...... with pressure DROPPING the whole while. Result would have been a terrible target and a hideously-fouled bore. But your bore is clear.

THIS has all the marks of a catastrophic Secondary Explosion: the powder starts slowly, does not raise pressure, heats up and suddenly it ALL flashes simultaneously, creating a pressure spike with a WAVE which is too high for the Receiver to handle. Yield strength of the materials used in the Carcano likely were OVER 95 kpsi, so it looks as if you exceeded that, blew the base off the casing and the gas leaked out (still at extreme pressure and trying to build) and fractured the Receiver Ring on its way out, hitting the Magazine in a burst and deforming it.

Normally, you can't get that powder to build that kind of pressure, not with a bullet in front of it which starts to move.

If it had been a "normal" extreme overload, the BOLT would have been damaged first, locking-lugs possibly sheared, definitely damaged likely by being deformed and pushed forward on the Bolt. You don't have that; your Bolt still works fine.

So that wasn't the problem.

That leaves us with the rare and mysterious Secondary Explosion theory.

Hope this helps.
 
To try and communicate what I am attempting to say, look at the cracked Receiver.

Normally, the Primer fires, lights the Powder, the Powder takes light and burns, builds pressure and the pressure moves the bullet into the bore, down the tube and expels it, and all in a thousandth of a second. It does this safely, time after time after time, because it TAKES that thousandth of a second. The pressure rises, stabilises, then falls as the Bullet passes down the Bore, then falls to zero when the Bullet exits. You can chart it with strain gauges, you can photograph it with spark-gaps or modern strobes.

In the situation we are looking at here, that did not happen. The primer fired, the powder did NOT light but it heated and then suddenly it ALL flashed, simultaneously. The pressure spike STRUCK the Receiver like a HAMMER, the entire shock of firing in perhaps a HUNDRED-thousandth of a second: much too fast for the steel of the Receiver to GIVE as it normally does when a Cartridge is fired. NO possibility of charting what happened because our instruments are not fast enough. Likely even spark-gap photos would just show the receiver letting go and leaking while, at the same time, the Magazine is bulging out.

What happened was fast enough that, to understand it completely, you would need computer simulations at a million-to-one time slowdown.

Such incidents are rare, very rare. How very rare? I have been messing with these things for 50 years now and they are rare enough that I NEVER thought I would ever be associated with such an event, even peripherally.

Yup: that rare.

I wish we were closer geographically. I would REALLY like to examine that rifle.
 
One can get into trouble with light loads. When the primer fires, it sends a shock wave through the propellant that is faster than the burn rate. It hurls the propellant forward where it strikes the base of the bullet and shatters into smaller granuals. The smaller granuals have a greater surface area and, therefore, a faster burning rate. This can give very high pressures before the bullet has started to move and give you a breech explosion. That is why you should always try to fill your casings to near capacity. If there little room for the propellant to move, it is unlikely to be shattered. If you really want a light load, put a bit of cotton wool into the casing on top of the powder to fill the extra space.
 
smellie said:
To try and communicate what I am attempting to say, look at the cracked Receiver.

Normally, the Primer fires, lights the Powder, the Powder takes light and burns, builds pressure and the pressure moves the bullet into the bore, down the tube and expels it, and all in a thousandth of a second. It does this safely, time after time after time, because it TAKES that thousandth of a second. The pressure rises, stabilises, then falls as the Bullet passes down the Bore, then falls to zero when the Bullet exits. You can chart it with strain gauges, you can photograph it with spark-gaps or modern strobes.

In the situation we are looking at here, that did not happen. The primer fired, the powder did NOT light but it heated and then suddenly it ALL flashed, simultaneously. The pressure spike STRUCK the Receiver like a HAMMER, the entire shock of firing in perhaps a HUNDRED-thousandth of a second: much too fast for the steel of the Receiver to GIVE as it normally does when a Cartridge is fired. NO possibility of charting what happened because our instruments are not fast enough. Likely even spark-gap photos would just show the receiver letting go and leaking while, at the same time, the Magazine is bulging out.

What happened was fast enough that, to understand it completely, you would need computer simulations at a million-to-one time slowdown.

Such incidents are rare, very rare. How very rare? I have been messing with these things for 50 years now and they are rare enough that I NEVER thought I would ever be associated with such an event, even peripherally.

Yup: that rare.

I wish we were closer geographically. I would REALLY like to examine that rifle.
Click to expand...

...swear to Gawd, smellie, you're channeling Hunter S Thomoson, there. ...
 
Smellie thank you for the explanation. I would have rather not experienced something this rare but has made for an interesting thread.

If you would like to see the rifle I'm willing to get it out to you. PM me

thanks

hogie
 
I know this is a serious necro thread but I think the end conclusion is incorrect. Hogie provided the answer several pages in.

hogie said:
The load data I used is from both 7th and 9th editions of Hornady reloading manuals. The 7th was published 2007, 9th 2012.

I found a post on GB forums with someone having issues with WIN 760. He was below there recommended start dalta of 35 gr. Blowing off the back of the cases. Was not using mag primers as well. When went to 35 gr and mag primers cases were ok.

I took an empty case seated bullet out .050" longer closed ok so that would rule out bullet being seated to deep. I put tape on the back of a case and it took .017" to make it hard to close. I don't know how excessive that would be, or if it even excessive.
Click to expand...

When I looked at the pics of the destroyed case the first thought that hit me was that this was an excess headspace issue. I'd actually experienced something similar myself a few years back.

Hogie roughly measured the headspace at .017" oversized. Normal headspace dimension has only a .004" range. That rifle was in a condition of massive excess headspace.

Excess headspace causes the case to stretch which can result in split or separated case head. Just like the pics show. The split case head allows 60,000 psi to jet into the receiver and can cause all kinds of damage, just like the pics show. The cracked receiver is a bit odd but maybe that rifle was just old or had a flaw that was only revealed by the ruptured case.

WRT SEE I highly doubt that a book published min load could cause it. Everything I've ever read about it requires an extremely low (less than 30% load volume) charge of rifle powder. Hoagie's ca 35gr load was nowhere near that low to cause SEE.
 
Ganderite said:
Do you load handgun? Do you have a can of 296?

Pistol powder will do that.

I cannot imagine 760 doing it.
Click to expand...

Yes to handgun, didn't mix powders,use bullseye and tight group. Still have the remaining powder in can. All there except for what I used to load with. Not sure what to do with remaining powder. It's the only ball powder I have used. All the loads I pulled were ball powder.
 
Suputin said:
Yes and yes. But I'm not gonna try and induce SEE.
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The only Winchester powder I have is 760. It is what I used not pistol powder.

I roughly measured headspace after the rifle blew up with a new case and tape, not very accurate. How much did the lugs get set back after this happened?

It could be excessive headspace, it could be SEE. There is some good explanation of SEE in this thread by smellie and buffdog. That is why I linked it to the thread about detonation in reloading.
 
Thanks for sharing Sir
Glasses are very important , however old rifles are not always safe as they appear, there is plenty of factors like metal fatigue hairline cracks not visible to the naked eye.
 
ironspear said:
Thanks for sharing Sir
Glasses are very important , however old rifles are not always safe as they appear, there is plenty of factors like metal fatigue hairline cracks not visible to the naked eye.
Click to expand...

Yes there could have been something there not visible.

I approach firing old rifles differently now. I bought a rest that I can strap rifle in and remote fire for first time. Has a shock system on it so rifle should not take damage.
 
ironspear said:
Thanks for sharing Sir
Glasses are very important , however old rifles are not always safe as they appear, there is plenty of factors like metal fatigue hairline cracks not visible to the naked eye.
Click to expand...

Even sometimes old ammo can be problematic. Years ago a friend was shooting a proven OK Mauser 98 when a case let go and sprayed both of us with burning powder and pulverized brass particles. As he was right behind the action he got the worst of it and was lucky to keep his vision as he had not been wearing safety glasses and took a particle of something right in the eyeball.

I come with built in eye protection being a life long glasses wearer but have been lucky to have only experienced a couple of potentially damaging incidents in my 30 years of shooting.
 
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