1858 remington barrel split

[Corkscrew Tom]

Not sure why this has gone into a discussion over the definition(s) of flash over and the like.

To clarify, 1) it was not a chain fire since I'm shooting cartridges, 2) from what I understand it was not a flash over as I'm filling up the case to within 1/4" or less of the top. DJ when I put 1.9cc into the case and measured down using a dowel and compared that to the BigLube bullet from the base to the crimp groove, I calculated about 1/16" compression. I will double check it again to make sure.

Reguardless of some folks coming out to say air gaps are not the problem once thought, I don't want to have them.

The cylinder does not appear to my eye to be harmed/damaged in any way and neither does the breech/threaded end of the barrel.

I'm still working on getting a clearer picture to post.

Thanks for all the inputs,
CorkscrewTom

[Blackpowder Burn]

Mako is by far the most technically astute person on this forum, and if he has a question or comment it should be taken seriously.  He is also unfailingly polite and professional.

I'd think really hard at least twice (or maybe three or four times) before I cast aspersions on him.   

[Corkscrew Tom]

Appologies,
That's the problem with type written communication. It's hard to convey the correct tense of a conversation. I meant no disrespect to anyone here. In my last post I was only trying clarify what I knew had happened and the type of loads I had shot. I agree with you, and read Mako's posts on many of the subjects posted here and have learned a lot about BP. I was just confused over the discussion on the flash over issue.
Keep em smoking,
CorkscrewTom

[Cuts Crooked]

Ok..........I've seen the term "flashover" used both ways that are being presented here. Different meanings attached to it each time....................and I understood what the individual using the term meant at the time.

So.....can we accept that there may well be more than one meaning to the term and move on? Or at least no more snide/snippy stuff.....Please?

[Mako]

Corkscrew - never heard or saw the likes of a long barrel crack on any handgun or rifle.  My guess is there were impurities in the bar steel for this barrel.  When the pressure and the sine wave was going down bore the impurities couldn't 'take it' and the barrel split.  Since barrel blanks are much longer and then cut to length - there has to be a few more around that look like this or will look like it

Hey John Boy how are you?

Actually long cracks along the length of the barrel is the most common failure beyond the chamber area on any barrel type. I have a slew of pictures, I'll show you a few.

Check this one out, it is a .50 caliber barrel, no explanation of the failure mode.  The shooter claimed he did everything right.



This shows a common obstruction failure on AR type barrels.  They were intentionally induced with barrel blockage for testing purposes:



Here are more rifles:







Here are some pistols:






This is a 1911 that still has the bullets lodged:




This is the funniest one even though the barrel didn't split.  It is a Single Six with the barrel totally clogged with .22 mag bullets.



Now this is an instrumented test of a .357 magnum load in a successful test to create the "detonation" phenomenon.  I have more with .38 spl loads.



The big splits and petaling of barrels starts out as cracks like Tom showed us and in the BP rifle barrel above.  Those both failed as they did because the pressures of BP are relatively low and the barrels are relatively thick compared to bore size.

Actually I have a lot more of every kind of goof up you can think of.  Interestingly enough the most common blown handguns are Glocks and Rugers.  M29 Smiths follow and then .45 Colt SAA clones.  I've been studying this kind of failure for over 30 years.  I'll take Cuts word for it but I have never read of a simultaneous contra ignition being called a "flash-over" in any publication including loading manuals etc.  I have a ridiculously large library of them for each of the bullet and powder manufacturers that extends back to about 1972.

Regards,
Mako

[Norton Commando]

A crack suggests fatigue, assuming no barrel obstructions, excessive loads or damage.  

Perhaps the barrel was made from abnormally low yield strength material. If this were the case, firing the gun with even "typical" powder charges will possibly create stresses above the endurance limit of the material.  And after enough cycles, the material develops a fatigue crack.

I suspect though, that the barrel on most black powder firearms is made from mild steel with a minimum yield strength in the neighborhood of 36,000 psi. It's difficult to get steel with yield strengths much less than 36ksi.  If, however, the barrel material is supposed to be say 60,000 psi, then I can certainly see where 36,000 psi material could be supplied by mistake.  And if the barrel's factor of safety is marginal with 60ksi material, then it will have a short life if 36kis material is used instead.

In order to get to the root cause, I think some $$$ would have to be spent in a lab testing the material and looking at the crack with a scanning electron microscope. Do we have any metallurgists here?  

[Montana Slim]

............
This shows a common obstruction failure on AR type barrels.  They were intentionally induced with barrel blockage for testing purposes:


............

IMHO, these are NOT examples of failure from a simple bore obstruction with M4 barrels. ...looks more like the effect of high-tempo firing schedules.

I have a file with hundreds of photos of simple bore obstruction failures in military M4/M16 rifles (cleaning rods, tips, bullets, paintballs, sand, etc, etc.....NONE have a burst barrel....oh, yes, I have at least a 1/2 dozen sectioned barrels showing the obstructions as well.

Note the original post faile photo has a longitudinal crack....and the crack may have propagated from the drilled hole for the barrel stud. Also note there is at least one other photo in this thread, of a octagonal barrel having a longitudinal crack...also present in this barrel is a drilled hole for a ferrule or such....humm(?).

Slim

[Mako]

Slim,
It's possible, I'll check tonight.  I'm in California right now and I am having a problem keeping my connection while I'm cooling my heels at an attorneys office.

~Mako

[Montana Slim]

Slim,
It's possible, I'll check tonight.  I'm in California right now and I am having a problem keeping my connection while I'm cooling my heels at an attorneys office.

~Mako

Hope things go well !! 
Slim  

[Mako]

Hope things go well !!  
Slim  

Slim,
Haaa... Yeah, did you know that attorneys can be a pain in the rear?  (Is that a rhetorical question, or a description?)  I'm one of three trustees for a survivors education/support fund and our third member is still deployed.  The fund bylaws require a yearly physical meeting and he won't be back until at least February now.  We are just trying to appoint a temporary third with his power of proxy until he gets back.

I must admit the firm has more "nerve" than I gave them credit for, they had three irritated Marines sitting in a conference room and a third on a telephone in the middle of a combat zone and they didn't seem too intimidated.  I guess it comes from sitting in a big chair all day with a view of the bay...  We should have suggested we all get on a plane (attorneys included) and fly over to Helmand and I think they may have been a bit more excited, or at least accommodating.

Yesterday one of the assistants loaned me their Ipad to keep me from pacing and I was having problems accessing certain sites.  That's all. No great intrigue, I'm not facing charges (yet)....  They are waiting on the signed hard copy to be verified by an "officer of a court" (a term attorneys use to make themselves feel important).  I loved it when they asked Tommy if there was a Notary where he was, there was just stony silence.  I never got the chance to reply because one of the other guys lit into them.  They were supposed to run the papers back on a supply flight last night for one of the Air Force legal officers to witness in the capital.  I guess some grunt  got a free trip to the Pashto equivalent of Disneyland for a day, wooopeee...

Woke up way too early, so I borrowed a notebook and headed out to beat the traffic downtown.  So here I am again drinking too much coffee and hanging around waiting for a phone call to come back into the office to sign the papers.

Regards,
Mako (who ain't killed no one "today")

[Mako]

Slim,
You're were right about the cause of failure of the M4 barrels in that picture.  The original post I got the picture from incorrectly identified the failure mechanism.  This follow up post explains the mix-up and identifies the failures as the result of high round count full auto testing.

http://www.ar15.com/archive/topic.html?b=3&f=118&t=243136

The point I was trying to make was that lengthwise cracks and splits are still the most common rupture type.  Even these barrels failed in that fashion.

I started thinking about what you said about M16 and M4 barrels not failing with obstructions in the barrels.  With the newer profiles the cross sections are a lot heavier in some areas.  I have a question since you've seen some of these tests, were the results the same with the old SP1 contours, or is this a phenomenon with the heavier barrels?

Regards,
Mako

[Montana Slim]

Essentially the same types of failures regardless of the pencil type barrel or the latest heavy barrel. - Obstructions haven't resulted in barrel failures. But, high pressure "events' from an obstruction plays heck with the bolt assembly, upper & magazine. One more good reason not to hold onto the magazine when letting fly.

Slim