Detonation Anyone?

[frankenfab]

While threads concerning this subject scare the living daylights outta me, I find myself drawn to them anyway--mostly to see what can be learned.

First--I AM GLAD YOU'RE ALL RIGHT, 390ish. I'm not sure how comfy I would be getting behind another rifle stock after having an experience like yours. I've managed to avoid any such incident (so far), and hope to keep that record intact. Knock on wood.

Yup, I have been all over this myself.

[Ragnarok]

Go over to the Gun Zone site..and dig around for M1A failure in the articals..you will find a few pics of a destroyed M1A rifle and another artical by the Fulton armory M14 guru(Clint McKee?)..with some structural analysis on the M1A's destroyed barrel. The barrel in this instance was was bogus..was improperly heat-treated to begin with..and over it's lifetime developed cracks at the land/groove junctions.

While the barrel on the M14 ripped like a banana peel from the breech forward..the similarity's to this cool old Ross's blowup stick in my mind...maybe it ain't the ammo?

From what I can gather the Ross was never made in .30-40 Krag, but was .303, .280(giant Ross), and .370(whatever this cartridge is?) and a couple other calibers...I dug around online for an hour googeling Ross rifles..and find no mention of Ross rifles being chambered for .30-40 from the factory.

So somewhere down the road this particular Ross got rebarreled. Just how good a barrel was this barrel?...Who made it?

[uscra112]

My wife has a professor at University of Virginia who wants to look at the scraps of the receiver through the department electron microscope. She told him what happened and he got all excited and started talking in scientific/pinhead/patois about crystalline shear and so on. He is going to email me. I would call that informed morbid curoisity.

NOW yer talkin' my language ! (Engineerese.) I've had access to an X-ray CAT scanner capable of not only scanning a cast iron engine block but also measuring the features it sees inside to an accuracy of a few microns, (in 3D). Ran a few receivers through that before they got too busy and started to ignore me. I've had scanning CMMs that could map a chamber against a CAD model to less than a micron. But an electron microscope - MAN am I jealous !!!

[390ish]

As best I could tell, this was a military model with a commercial stock because the stock had not been much messed with outside of some cosmetics. Not really shaped like the military stock, as I used to have one of those in 303 and traded it.

I took more photos, but with my phone again. My daughter was playing with the camera and it is now missing. One of the shots is the remnant of roll mark/stamp. This rifle was rechambered in 30-40 Krag and stamp read "CAL 30-40" and the gun retained its factory barrel, which was undoubtedly 303 british. The barrel retained the crossed pennant proof with the "C" mark from Canada that matched other Ross rifles on line. I never slugged the bore, but it shot cast bullets sized 311 very well.

Did only so-so with factory 30-40 ammo.

Partial caliber stamp:


Front view of action -- some washout from flash on broken metal:


Barrel views (3):






Pieces people picked up and gave to me:


Reverse view of pieces


The one in the lower left has crack, if that matters. My wife gave the contact info for the professor with the electron microscope. I talked to an engineer buddy today and he said it would not be difficult for a person (metallurgist) with the know how to tell if the metal had become plasticine over time giving rise to a crack or if the stress causing the break occurred all at once. I have probably run about 200-225 rounds total through the gun in the three or so years that I owned it.

[303Guy]

Holy cow! I didn't realise the chamber had blown. My late Uncle was the workshop manager at Musgrave in SA and he told me of a 308 cartridge being fired in a 270 on their test range and that the receiver split open and let the barrel go downrange. He said the barrel was undamaged i.e. re-usable. (The boolit hit the target). This was a test range so the gun was fired remotely so no safety issues.

In that instance there was extreme excess pressure involved. For a rifle chamber to burst like that? Not bulge or or distort then pop, just crack open like it was brittle. A gun barrel isn't brittle normally. It's tough but not hard. Unless of course the pressure spiked as in a detonation - then even softer steels would shatter. So could it be a true detonation? Could this happen again to someone else in another gun?

[Larry Gibson]

Got to say the way the chamber was blown that there was indeed a bore obstruction. Hard to say whether from an SEE event, 2 bullets in the case (possible from 390ish's earlier description of loose necks) or some got into or was left in the barrel. Very reminiscent of an M16A2 that blew....had a jag with patch left in the bore just in front of the chamber. I'd lean more toward 2 bullets inadvertently put into the case..........glad 390ish is basically alright. Too bad about the rifle.

BTW; I shoot a Ross Mk10 .303 quite often and don't take the bolt apart. It takes healthier loads than the SMLE but I keep psi's down in the 55,000 psi range. Rivals the '06 with 150 gr bullets having the reamed out (basically improved) chamber and the 29"+ barrel length.

Larry Gibson

[390ish]

Only only one bullet was seated in the case. Loading was accomplished about 2 hours before firing. Two bullets in a case would be silly. My supposition was that upon seating, the crimp on the bullet may have broken and the bullet slid down into the case.

Larry, do you load to 55k psi range with cast in Ross, or is that with jacketed bullets? I have been unable to determine if the proof rating of 62k psi on the 1910 model holds true with the 1905 model. Do you know?

This rifle had a 303 Brit bore rechambered to 30-40, which is smaller in diameter and with lower pressure than the 303.

[excess650]

I'll be curious to hear the results from the autopsy, but it sure looks like crystallized (brittle) metal to me. Steel from over 100 years ago is far different from the steel we've become accustomed to using in rifle barrels and receivers. Too, heat treatment has come a long way. I wouldn't be surprised if that old Ross was just case hardened, but just speculating.

The pictures from the phone are way better than some guys' camera photos.

[Larry Gibson]

390ish

"Larry, do you load to 55k psi range with cast in Ross, or is that with jacketed bullets? I have been unable to determine if the proof rating of 62k psi on the 1910 model holds true with the 1905 model. Do you know?"

That 55 psi is with jacketed bullets. My cast bullet loads with 311299 and 4895 with a dacron filler are around 23-25,000 psi depending on the flavor of 4895.

Understand that the 62K proof rating on the 1910 model is in C.U.P. "psi's". That is a much different figure these days using piezo transducers and strain gauges. I would suppose the 1905 used the standard .303 proof load(?) but that is just a guess. Perhaps some of our Canadian members know?

Larry Gibson

[303Guy]

I've seen a 22rf barrel split from the breach end a few inches along.

I can't help thinking there was nothing 390ish did that could have cause this. On the boolit being pushed back into the case, would that possibly have pushed pressure into detonation zone? The boolit canted so it could not move down the bore?

Then, assuming there was a bore obstruction, would there be enough energy from the charge to blow the gun? It was a lead boolit. It could have swaged and been flame eroded? Where did it go? It would be interesting to know if it hit the target or just got mashed and flame cut. Is there any sign of lead dust in the bore?

You know 390ish, as curious as this is it is not really fun. Seeing a fine rifle like that destroyed in seconds is actually quite sad. Of course I an greatful that you were not seriously injured, but the loss of that rifle ....

[390ish]

Thought I would update those of you who are interested.

I heard back from Tom Griffin at the Lyman laboratory. He said that he "tended to agree" with Johan at Accurate powder on this being a metallurgical rather than an overpressure issue.

"Hi Spencer,

Thank you for the additional info. Glad to hear that you did not have any serious injuries. From the damage that was done, it could have easily happened. It is really a shame that this happened to such a unique rifle also. I wish that I had a definite answer for what happened, although I would tend to agree with Johan. With the added safety factor of the rifle originally being chambered for the higher pressure 303 British cartridge, it would seem likely that the charge would have needed to be well over 28 grains to get into a serious pressure problem. I would not want to try to speculate on what charge would be needed to get up to the 45K, 50K, or 60K area, but would think that the case would be close to filled. If the professor does examine the metal, I would certainly be interested to know the outcome.

Tom"

[Southron Sanders]

First of All, I am Glad that you are O.K.

You might never know what caused your gun to blow up. Personally, I would never shoot a Ross.

Replace your Ross with a "High Number" Springfield '03. They are safe and the '06 can be loaded with cast bullets.

[Rokkit Syinss]

Glad to hear you're not seriously hurt. Some of the fractured areas look to have different coloration but that could be the fact you're using a phone to take the pics. The discoloration however does look similar to some fractured metals I have seen. Stress corrosion cracking maybe?

[303Guy]

I was looking at those discolourations too. Note also how the fracture at the chamber end has multiple faults. And why would the top piece break off at the thickest part of the barrel like that? Why not just bend up?

[390ish]

Engineer buddy of mine looked at it today. He is a retired mechanical engineer who worked at oil drill sites. He really cued in on what Rockkit Syniss said. There was oil that appeared to penetrate some of the crack sites. He thinks that the barrel may have been screwed into the receiver too tight. I don't remember all the terms he used, but in a nut shell, it started out as one or two small cracks that grew in a slow, linear nature.

The way he explained it was that the steel retains much of strength, even when it is cracking, then it reaches a point where it just completely fails. He thought that the crystalline look of the breaks was suggestive of the ductile steel being worked over time to where it became brittle. Thought that bad heat treating would not have lasted as long it did on a rifle and that it likely came from overtightening the barrel. I guess when it was re-chambered someone likely took the barrel off and then over tightened it, or just turned it in a rotation when there was not enough room for it, then rechambered.

On the plus side, the pan lube that I made up seemed to work well. Only a hint of leading in the barrel, and that might have been left over from the old liquid alox rounds I used previously. Going to head back to the range tomorrow and get my head right again.

[303Guy]

I understand the mechanism of under-tightened bolt failure and also of over-tightening thread stripping failure but a chamber shattering from over-tightening? I'm afraid I will have to disagree with the over-tightening hypotheses. The edge-line of the thread is visible in one of the photo's and I see no sign of thread damage, let alone from over-tightening. In all my years in the engineering field I have not seen proof of over-tightening failure of that nature. It's cyclic stress that causes stress fatigue failure and over-tightening does not do that. Under-tightening does. Well, over-tightening something to the point where it gets strained into the failure zone will cause a failure but that won't be longitudinal. I'm just saying I don't thinks so.

[geargnasher]

I tend to agree with 303Guy. It's been a long time since I did any substantial amount of failure analysis, but it looks to me that if the barrel was overtorqued in the receiver, the receiver would have failed and the barrel would simply have been blown forward as the receiver split. But it seems that the failure originated in the forward part of the chamber body, just ahead of the end of the receiver. It sure looks like Cosmoline seeped into some of those cracks, question is did it do so before or after the Kaboom?

Could be fatigue cracks from abuse in a previous life allowing the chamber metal to finally give up the ghost all at once, or it could be the boolit acted as an obstruction somehow.

Gear

[Larry Gibson]

+ another on 303Guy's comments. This is a very plain example of destruction from a bore obstruction.

Larry Gibson

[243winxb]

Powder problem - to much or wrong kind. Bore Obstruction-Bulged and/or split barrel. One or the other.

[BCB]

Powder problem - to much or wrong kind. Bore Obstruction-Bulged and/or split barrel. One or the other.

In one of the very early posts on my part, I said a bore obstruction--period...

I assumed he used the powder he listed--if not, then the wrong powder factor comes into play as stated by 243winxb...

It is just plain and simple...

Sorry engineers, sometimes we don't need to get to the atomic level of composition and structure to figure out what the problem might be...

If you’re holding a stick of dynamite and someone lights the fuse, we don't need to understand how or why dynamite explodes but we understand where you end up!!!

Sorry for the rant, but facts are sometimes facts...

Glad no one got hurt...

BCB