Lucky day?

I just slugged the bore, .268 on the nose. No problem there, recheck COL all in spec. I full length sized the brass with Lee set with the large mandrel before loading so I would not have too much neck tension. I just checked for max length, all were under. The case holds about 49 gr of powder to the top of the neck mouth, not a double charge.

Everything I have checked so far has been in spec as far as My loads go.

Not sure why it happened
 
hogie said:
I just slugged the bore, .268 on the nose. No problem there, recheck COL all in spec. I full length sized the brass with Lee set with the large mandrel before loading so I would not have too much neck tension. I just checked for max length, all were under. The case holds about 49 gr of powder to the top of the neck mouth, not a double charge.

Everything I have checked so far has been in spec as far as My loads go.

Not sure why it happened
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That's very strange. You've defiantly ruled out pretty much everything. So you're left with bad brass (plausible it does happen), a gun with a fault that maybe wasn't visible to the naked eye ( like extremely loose headspace). The other thing is maybe, and this is a long shot but just maybe it's a mis marked bottle of powder??

And I might add that yesterday doing 30 grain loads I made note that about 2/3 of the case was full so I'd say unless you were shooting case loads with flake powder it's damn near impossible to double charge a carcano round.

This is strange!!
 
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desporterizer said:
I am thinking incorrectly labeled powder too. To crack the receiver take stupid pressure and look at the stock!
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I'm leaning that way myself. I own the same gun and it's a stout little rifle. I'll have to look later but there's a video on YouTube showing what happened when the maker of the video shot a way oversized bullet in a small spec carcano bore. It shows the brass is completely destroyed at the back end but the rifle held together just fine.
 
Yes, the "CAL. 6.5" is correct and original to this rifle. The original Model 38 was a 7.35 but thy changed back to the 6.5 once the war got rolling. The Model 38 was continued in production as a 6.5 for a whole raft of reasons, all of them good and all of them making sense.

The original powder used in the Italian 6.5 ammo was Ballistite, a very fast double-base flake powder. It worked very well in a 30.9-grain charge for the FUCILE, the TRUPPI SPEZIALI and the CARABINA: barrel lengths 32, 21 and 17 inches respectively. This rifle is a TS.

But the powder used was W-760, a Ball powder and quite a slow one. It is a powder generally used for heavy loads in large casings to be shot in long barrels. THIS is a situation of a small casing in a short barrel.

One thing we can say: Carcanos are STRONG little rifles.

I saw this thread very early this morning and it disturbed me, taking me back to articles I read 50 years ago, when I was just starting out. The articles referred to a number of rifles destroyed in similar fashion, all with the same general characteristics: very slow powder, light charge, complete destruction of the rifles.

BUFFDOG is nobody's fool; he remembers those incidents as well.

I think everyone would do well to read his post VERY carefully. It offers the only LOGICAL explanation to this otherwise-unsolvable mystery.

This is why I try to use only FAST powders in my rifles; I like light loads but I can't afford new rifles all the time.

Happy there was no SERIOUS injury.

Hope this helps.
 
I have a "Cooey Carcano" that is stamped 6.5mm. Could there be a hint there?
 
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KJOHN, the "Cooey Carcanos" were supposed to be in 6.5x54 Mannlicher-Schoenaur, that being the only 6.5 ammunition manufactured in Canada at that time.

Eaton's did have some "special" ammunition made for their rifles. It came 20 rounds in a PINK box, headstamp was just "R" at 12 o'clock, "6.5mm" at 6 o'clock.

I'm pretty sure I have 2 rounds here, so I will have to look them out and measure them.
 
So Smellie, you have solved the mystery?

Slow powder in a reduced charge is what caused this rifle to literally blow up??
Very interesting that such a load is published in a reloading book.

I guess this is a good reason to have several load data books to cross reference data.
 
I did a double check on the powder container, the label has not been disturbed. I did a quick web search of WIN 760 and Carcano, no major problems. The tough part for reloading the older calibers is finding data from a manual. Hornady has been good for data.

Question for Tinman204, what powder are you using for your reloads? Are you using the Hornady reloading data.

May have been a headspace problem, Are there any ways to check with a new piece of brass. I can still operate the bolt and checked to see if brass will chamber, it will.

I have taken pictures of the Hornady data, and there writeup on the .267 bullet. Not sure if they can be posted because copyright issues.
 
I remember my PAL instructor briefly covered a scenario where a light load with a certain powder could cause the kinds of pressures we are looking at here. He said nobody has been able to replicate it through testing even though it can and does happen on extremely rare occasions.
 
My loads were 30 grains of IMR 4198 which is a very fast powder.
Bullets were 140gr .264 Winchester bullets and the .268 160gr hornaday.

I wasn't using this load off of any of my reloading books, as they don't list this powder. I got the load from a CGN member who is my mentor and is someone I really trust.

EDIT: I just checked 2 of my books and there's no load data for the powder you have listed.
 
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buffdog said:
The pictures indicate a typical high pressure incident. The reason Winchester recommends Magnum primers is that 760 powder is a bit more difficult to ignite, especially in reduced or lighter loads. There are also some cartridges that it is not suited for. One case comes to mind where I was on the range and a guy had loaded lighter loads of Winchester 760 powder in a 7mm Remington Magnum, and was getting serious hang fires with an appreciable delay between the firing pin falling and finally the round going off.

There is also what is known as "secondary explosion effect" and this has been documented in larger cartridges, first noted in the 270 Winchester. Basically what apparently happens is a reduced load will go off inside the cartridge but create a shock wave. This shock wave then comes up against the bullet, and the bullet seems to act as an obstruction thus creating much higher pressure. Some powders, like IMR-4895 can be used with 80% loads, but other powders are not suitable.

With a 35 grain load, I am not sure if you could double charge a Carcano case with 70 grains of Winchester 760. Right now, I have to go to work so I do not have the time to try it but maybe someone else can.

This leaves a cartridge brass case failure as a possibility, with weak brass in the head area, or possibly a headspace problem. As pointed , the Carcano action is quite a strong one. However, I do see that there is "Cal 6.5" stamped on the sight. Military rifles did not have this, so it would seem that this rifle has been looked at, and possibly been rechambered for another cartridge.

Was the Winchester 760 from a NEW can, or did you buy it from another source, such as at a Gun Show? Buying unsealed cans of powder is dangerous. Have you used powder from this particular can of 760 before, or is this the first time? Have you fired your Carcano before, or is this the first time?

Once again, it shows the value of wearing shooting glasses or safety glasses. Thankfully, it did not do a lot more serious damage, especially to your eyes.
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a similar scenario i have heard of involves the case being around half full or less. when the primer fires, it forces the bullet into the lands, at the same time the flame front ignites a huge portion of the powder at once. the now stopped bullet is effectively seated way too long, and the burn rate of the powder is much faster than usual, causing a spike in pressure in an otherwise safe load
 
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 data 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.

Thanks for your info Tinman204.

Thanks to everyone who has posted with insight as to what may have happened.

hogie
 
scott585 said:
a similar scenario i have heard of involves the case being around half full or less. when the primer fires, it forces the bullet into the lands, at the same time the flame front ignites a huge portion of the powder at once. the now stopped bullet is effectively seated way too long, and the burn rate of the powder is much faster than usual, causing a spike in pressure in an otherwise safe load
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This is basically the idea of the "secondary explosion effect." As mentioned, it is very difficult to duplicate, but it is possible. The American NRA did some tests and finally got one out of over 1000 rounds to do this.

If you do not put ANY powder into a cartridge case and chamber and fire it, the chances are the force of the primer alone will move the bullet out into the rifling, and thus create a larger internal area within the chamber as the bullet has now moved out of the cartridge case and has become an obstruction in the barrel.

When reloading cartridges, it is well mentioned that it is recommended that the powder fills most of the case, at least to the shoulder. This makes sure that the powder is up against the primer fully at the back of the case. Reduced loads such as cast bullets recommend much faster burning and easier to ignite powders, such as the flake powders, (Red Dot, 2400, etc) or the tubular powders, (4227, etc.) Ball powders, usually having a coating and smaller surface area of each individual grain of the powder, are much harder to ignite.

When you use a reduced load, the powder is NOT fully up against the primer, but lays on the bottom of the case because the rifle is held horizontally. This means that there is an air space ABOVE the powder in the case in most instances of reduced loads. With a hard to ignite powder, when the primer fires, most of the force can pass OVER the powder in this air space, because of the lesser resistance, and thus pushes the bullet out of the case into the rifling where it now becomes an obstruction. However, some of the flaming particles of the priming compound eventually find their way into the powder, and the powder ignites.

When a cartridge is "normal" and the primer fires directly into the powder that is pushed up against the primer, the primer flame shoots through the center of the powder charge and thus ignites a large area, setting off the charge and shoves the bullet forward. In many cases, the bullet is started moving before the powder charge is fully consumed but the big factor is that the bullet is MOVING down the barrel.

With a reduced load, the powder charge is consumed at a more progressive rate due to the smaller INITIAL area that gets ignited by the primer. This creates a slightly different "spike" in the burning characteristics and pressure. When the gas formed by the ignition of the reduced load expands, it is now in a CLOSED container, due to the bullet being lodged in the barrel. It is now a BOMB, and the pressure has to escape at the most weak area, which in most cases, is the brass cartridge case.

I am not talking about a long period of time here - it happens in Milliseconds. The above is a very shortened and simplified version of what can happen, even though the charge of powder is well below the maximum charge recommended.

As SMELLIE mentioned, we, being a couple of old farts who were around during the 1950s and 1960s, were aware of the possibilities of this happening. This is why we use the faster burning powders for our reduced loads, and select powders that have proven "tried and true." One of our favorite CAST bullet loads for military rifles is 13.0 grains of Red Dot, a miniscule charge in something like the 30-06. But it works very well, because Red Dot is a flake, easy to ignite powder, and we use CAST lead bullets. I would NOT use COPPER JACKETED BULLETS with this load, as you could easily end up with one stuck in the barrel.

It also comes down to selecting an appropriate powder, primer, and bullet weight combination. In the smaller calibres, such as the .223, 6.5 Italian, and even the .308, the medium burning powders seem to give the better results with adequate or higher velocities and accuracy. The slower burning powders give good results in larger cases and heavier bullets.

Gun Shows are an excellent source of information on the older or more obscure calibres. You can usually buy the older reloading manuals at a very reasonable price, and these manuals were made when the Era of lots of Surplus rifles, (after WWII) were readily available, and reloading was starting to gain momentum as a Hobby. I sometimes buy them, and give them to a newer member to the Milsurps shooting fraternity, because I know that the person has a particular type of Rifle. TINMAN204 was the recipient of one such manual at the Dauphin Gun Show a couple of weeks ago.

ADDITIONAL - I was a bit curious so I "Googled" the Internet for "Secondary Explosion Effects" and found pages of Posts and Information on the subject, including lots of pictures.
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smellie said:
I saw this thread very early this morning and it disturbed me, taking me back to articles I read 50 years ago, when I was just starting out. The articles referred to a number of rifles destroyed in similar fashion, all with the same general characteristics: very slow powder, light charge, complete destruction of the rifles.


I think everyone would do well to read his post VERY carefully. It offers the only LOGICAL explanation to this otherwise-unsolvable mystery.
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I agree. Something all of us who roll our own should be aware of. Perhaps this thread should also be featured in the relaoding forum as well.
 
If this is the case, why does Hornady list a load for w760? I do remember a site dedicated to carcano recommending not using anything slower than 748.
 
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