The recent posts by CRUSHER about his barrel problem and previous posts from others describing locking lug set back/ headspace problems developing in Big Bores has really ignited my interest in what real personal experiences the forum members have had with Catastrophic events and if they were able to diagnose the cause of the problem. Given that few of us have actual pressure measurement instruments, how far can certain cartridges and actions i,e the Lott actually be pushed and what are the warning signs if any of imminent failure. The CZ550 comes to mind as many of us have pushed it way beyond its rated pressure levels. Should this be continued or are we playing with a ticking time bomb?
Given that many here are pushing the envelope with various wildcats, rebores, rechambers, twist rates and land number, monometal bullets in Doubles etc as well as questionable reloading practices. There is undoubtably a list of do's and don't that could be compiled. I believe there is quite a bit of OLD Gunsmith lore that may or may not be true.
I'm looking for a serious discussion here with pictures if possible of blown up guns/actions etc as well as the owners
anecdotal experience.
Lets here of your experiences and observations.

RGB - great topic, thanks for bringing to attention -

Since I have never "blown up" or splattering any firearm (I tend to reload a bit on the conservative side), I can't contribute from personal, first hand experience so I will be on the sidelines on this one.

But man oh man, have I heard some stories...

KMule

hey rob I think my problem was caused by faulty bbl or excesive wear not over presure the ammo I was shooting was factory and to saami spec. I dont think this was a presure problem as much as a shal we say barell failure. it is thin for my tasts at the muzzle but .749 but not realy thin enough to have caused this on its own. I just could not trust this bbl enough to cut it off and use it again I may be overreacting but I think replaceing it is the only way to go.

It is a fasinating topic and while I'd prefer actual experience, I'm open to hearing the anecdotal stories too.
Speaking of Lore, I was taught that minimal muzzel thickness must never be less than .125 " each side of the hole" by the Great Mr. Selner a NJ gunsmith who I apprenticed with many years ago. Your muzzel thickness should be a little over .145 so the belling should not have happened. Can you take some pictures of your barrel for us? Did it expand externally? Can you feel a buldge of any sort? It would also be instructive if you could get soem idea of the hardness of your barrel. SS or chromoly? etc.
We should all learn as much as possible from this.
Personally, I have examined more than one Argentine M98 mauser action with clearly set back action locking lugs that had been used on Weatherby 300's and 7mm's. The set back resulted in excessive headspace and the bolts both had to be opened with a hammer after firing. Conclusion Soft action insufficiently heat treated.

rob its chromoly you cant tel from the outside anything at all is wrong but when you put some penetrating oil on the muzzle you can see it is cracked the guy I got the barellfrom who
"thought it was a douglas or krieger" now thinks it was a shaw or something else. I think it was just a shit blank and the low presure cast stuff it shot for years did not show the problem. I took some pics will post tonight but I dont think you can see the problem in them.

Crusher- You might try some Close up pics to see the crack you describe. Maybe point a pencil towards it. I have some pics of barrels that exploded from the muzzel and unfolded backwards like an umbrella and I wonder if that started from a similar crack. If so you were very lucky!-Rob

Rob (aka Antigen Presenting Cell/Armoured Personnel Carrier/Apocalypse Production Chief):

Great topic. I have never had any blowups or pressure problems related to twist, of course this is on the order of the difference between a 15" and a 10" twist, and pretty negligible.

Seriously, good topic to be followed by all and contributed to in any possible way.

I have never had any misadventures. I do recall Alf was pissed by setting back the lugs on a Mauser 98 .500 Jeffery after trying some load data he found recommended on this site.

The CZ 550 Magnum action for .505 Gibbs is marked with a pressure limit equivalent to about 55,000 psi. More than enough pressure for classic ballistics which are probably more like 40,000 psi.

Lug setback from excessive bolt thrust with the big cases?

Failure of locking lug recess on a Mauser 98 opened to the front?

Barrel splitting on stainless steel more likely than chromoly?

Etc., etc., lot of possibilities here.

Thank you APC.

What type of steel was Crusher's barrel ? 4140, 416 etc ? Free machining grades would have more potential problems especially if of poor quality [Tikka/Sako !] and of course would be sensitive to cracking with thin bore.Is the cracking in one place or more than one ?

RIP- Well said! Yes, I do remember AlF's experience. IS he still around? I have not heard from him lately.
The CZ550 is as you state rated at 55KPSI and given the bolt thrust of some of the cartridges we have stuffed into it, to date I've had no reports of lug setback. I have taken .600OK number 1 apart and measured the lug recesses vs my original unfired dimensions and found no changes after approx. 100 rds. Will that still be true after 1000? Don't know. I have heard of no action problems from other .600Ok users, so is the CZ550 actually under-rated by the factory?
I have heard reports of Weatherby Mk V actions shearing locking lugs but have no proof unless someone here volunteers it.-Rob

I have had one gun blowup experience.

I loaded a 6.5 mm Ariasaka with 38.0 grains of Bullseye powder and seated a 160 grain Hornady round nose bullet. F215 primer. Then I placed a .257" 120 grain Sierra spitzer boat tail in the bore to create a barrel obstruction, tied the gun to a tree and pulled the trigger with a string.

The bottom metal and extractor blew off and I could not find them. The stock cracked through the magazine area. The bolt release was loose and floppy and I could not open the bolt. A friend later got the bolt open. The lugs had been set back. There was no damage to the barrel. There were no powder burns on the gun and probably I could have fired the rifle from my hands without injury. The rifle could have been put back together again by fiberglassing the stock cracks, lapping in the set back lugs, turning the barrel in to correct headspace, installing new bottom metal and fixing the bolt release.

An Arisaka is just a Japanese version of a Mauser 98 (uglified, of course), and I was pretty impressed at how well it held together.

500 grains- Dan- Good post- In my ill spent youth I tried a similar experiment with a Arisaka but in 7.7mm. Full case of Bullseye and the action only tied to a tire. The barrel seemed OK, brass case head ruptured and blew out the extractor jamming the action. Right bolt lug was cracked but did not shear off and action locking lugs set back so deeply I had to hammer the action open.. This gun could not have been refired and the shooter would have been hurt by the escaping gases.
Didn't Saeed have some pics of a gun they blew in a water tank a few years ago?-Rob

Never had one personally, but often wonder if I caused one When I first started reloading, I was a poor student, whose prize possesion was an 8x57 CZ full stock Mauser, that I got on a good deal. I was short of brass and a friend gave me a couple of boxes of 30/06. I trimmed the cases, sized and reloaded them, putting them back in the 30/06 labelled boxes. The car I owned didn't lock, but on my first hunting trip, I left one box lying on the dash. When I came back, someone had stolen them. I'm still thinking somewhere out there is some guy who got one hell of a surprise.
Grizz

Lug setback is usually to lack of proper hardening. It is probably the biggest cost for a do it yourself gunsmith when doing any action work on your beloved mauser. Also the action should be annealed prior to rehardening to be proper.

I had seen a M16 let go on what was determined to be a overcharged case. Elbow to elbow looking for cast aluminum and parts isn't much fun. Shooter uninjured.

No blown up rifle stories. I know of two different 12 ga shotguns that blew their barrels up. One from a 20ga shell in the bore, and the other, presumably, from an OVERLY hot factory slug load (nothing metallurgically could be found with the barrel and the fracture was a single over load).

I have blown a great many primers ie case head in my time though. Primarily 308 Win and 303 Brit. The rifles, once cleared, kept right on firing.

Can anyone confirm the English double rifle story where supposedly the use of monometal bullets ironed the rifling to the outside of the thin barrels? I had heard this occured on a Holland and Holland or some similar high end gun but can't confirm it. Maybe some of you can.
I also seem to remember someone showing pictures on the AR gunsmithing board of a new model winchester M1895 in .405 win that let go
directly over the chamber throat area.. I think this was diagnosed as caused by a un-trimmed ( way too long) brass cartridge being jammed into a short throat.. Any one remember that one?-Rob

Great signature line, Rob APC.

Graeme Wright's book, _Shooting the British Double Rifle_, discusses the not uncommon problem of antique double rifles that show the rifling having become visible on the surface of the barrels, ironed through by the passage of steel-jacketed solids, IIRC.

And that suggests a point I gleaned from the Alexander Gray book:

Pre-WWII gun steels in the old doubles had significant lead content in the alloy, and were heavier and weaker steels than the modern chromoly stuff like Krupp Stahl.

Even a Tikka stainless-fluted-featherweight barrel would be stronger than the antique double barrels made thin-walled with heavy and weak steel to balance properly for proper gentlemen. Pinky finger salute!

Where are the pictures of exploded actions and barrels peeled back like bananas? Incoming ...

quote:

Originally posted by Robgunbuilder:
Speaking of Lore, I was taught that minimal muzzel thickness must never be less than .125" each side of the hole" by the Great Mr. Selner a NJ gunsmith who I apprenticed with many years ago.

I've included the above quote in regard to your subsequent question about doubles, because it's a point worth making. A few of the current lower end doubles might well have that much wall thickness, but most double rifles don't, and many are nowhere near that. Most are under .100". For example, the last Holland Royal .465 I measured was just under .090", and a friend has a Dominion .465 that is .086". Heym's new Model 88B in .450/.400 with 26" barrels will be 15 mm at the muzzles, or .090" wall. I measured a couple of current Chapuis in 9.3X74R recently that went .522" and .524", or .078" to .079" wall thickness.

quote:

Originally posted by Robgunbuilder:
Can anyone confirm the English double rifle story where supposedly the use of monometal bullets ironed the rifling to the outside of the thin barrels? I had heard this occured on a Holland and Holland or some similar high end gun but can't confirm it.

I got it direct from Holland when I was in their shop in 1992. A customer ordered a new .465 Royal and stipulated that he wanted it regulated with monolithic solids. Holland had had enough rifles come through with rifling on the outside of the barrels by that time to figure out what it was from, and refused to be responsible for what might happen. By the time the regulator got finished with it, the rifling imprint on the outside of the tubes was severe. This was a new rifle, not yet finished (in the white), with barrels of modern steel.

The issue has to do with the wall thickness necessary for a nice double, and has little to do with old vs new steel. .125" is fine for a single barrel rifle, but it makes for a clunk of a double.
----------------------------------------------
"Serious rifles have two barrels, everything else just burns gunpowder."

Back in about '95 while I was still at Dakota I had a 416 Dakota come unglued on the bench, due to very bad ammo and A-squares latest greatest no web case design. not a happy time.
The load that I ordered, from a source that I will not name was 350gr swift 86.0gr RL 22.
The load that blew the shit out of that rifle and almost me was 400gr swift and 96.0 RL 15 DOH!
My first thought was "that was really load" louder than normal! It almost knocked me out! like getting punched really hard. As I came around, the rifle was still smoking. It puffed up the magazine box way, way bigger blew both side panels off the stock, I never found the extractor the floorplate got bent until it let go of the latch in the guard. Set the lugs .020 into the action swelled the chamber melted brass of course all around in the breech. I did hit the target just the one time with that rifle. My shooting glasses where pock'd. My face around the edges of my glasses had about a dozen or so bleeding little pin holes, a couple days later I had a shard of brass come festering out from under my thumb nail. The receiver held together, but the gas and particle control was severely lacking. I would have loved to see that with a high speed camera i'll bet that rifle had gas squirting out every possible place. After that I picked up a 7 Mag and continued my day of testing rifles seemed like there was a Rigby and a 338 in that bunch that day. I remember telling Norma, that one can't go, cause it blew up, the look on her face was priceless, utter shock and amazement. I was cool as cucumber, and real happy to still be in one piece, with far greater respect for the M-98 design and a better understanding of what to look for in pressure signs. When the stock disintegrates, back 'er down half a grain you should be good there, HA HA.
Timan

quote:

Originally posted by Robgunbuilder:
Can anyone confirm the English double rifle story where supposedly the use of monometal bullets ironed the rifling to the outside of the thin barrels?

I have seen one British double where, if held up to the light, the rifling pattern could be seen on the outside of both barrels. Supposedly the rifle had been shooting Barnes X bullets. However, it remained in regulation and shot well.

What I do not know is whether the rifling marks were already visible on the outside of the barrel before Barnes X were shot in the rifle. Perhaps some of those old steel-lined Kynoch solids were the culprit many years ago.

My father blew one up years ago -- admittedly it was either a 30-06, or 300 Win Mag (he swapped rounds somehow, but I can remember which way -- he became very adament about only 1 caliber at a time at the range.) He was fine, and actually had the gun repaired. A good design should not allow any serious harm to come to the shooter. (Admittedly, if you fill a 505 gibbs or 50 BMG w. pistol powder...)

quote:

Originally posted by RIP:
Great signature line, Rob APC.

Graeme Wright's book, _Shooting the British Double Rifle_, has a picture of one of the antique double rifles that shows the rifling having become visible on the surface of the barrels, ironed through by the passage of steel-jacketed solids, IIRC.

My My MY, i wonder if THAT rifle had been shooting Barnes bullets? ...wait a second, they predate barnes solids...
LOL

Aglifter,

You're not going to get us started on Aggie jokes are you

Do you think a .300 Win Mag can fit in a .30-06 chamber or fit the .473" bolt face?

I made the mistake once of shooting a .257 weatherby and a .338 win in the same session. My buddy handed me a .257wby and I stuck it in the .338. It fired with a dull report and out popped a perfectly fireformed .338win with a .257 weatherby headstamp. Scared the crap out of me when I realized what had happened. No damage to the barrel from that .257 bullet skipping down it as far as I could see.-Rob

There is a interesting story on the AR Gunsmithing site called TODBARTELLS GUN ACCIDENT. Do a search and its easily found, 2001 vintage
He had a .308 Norma Mag built on a P17 blow-up that appears to have been caused by a bullet sticking in the bore about 13.5 inches in and the casehead letting go. Seems he experienced case head separations previously but continued to shoot the gun. The consensus is a combination of excessive headspace, wrong powder perhaps all contributing to a Secondary Explosion effect. Bullet is pushed out of the case into the bore and stops, delayed powder ignites in a larger volume later and stuck bullet acts essentially as a bore obstuction. The week point is the case head and it lets go.
Shooter nearly lost his eye.
This is a good example of the importance of assuring good headspace when using belted cases.-Rob

M70 Convertible (not mine) photos from AR some time ago, cant find thread.

quote:

Originally posted by Woodjack:

If that were a Leupold, at least he would get a new scope out of it.

here are some pictures of where the cracks in my muzzle are.

maybe you can see it better from this angle

The second set of photos from CRUSHER demonstrates the cracks very well.

Is that a the result of firing it after the cracks were noted?

Are you O.K. CRUSHER? How many fingers can you hold up and count for me?

Ron,
I shook his right hand about 2 years ago, and it seemed to be all intact..

Crusher, FUNNY way to present the pics..


and thank GOD I haven't had these experiences

it will be interesting to see if any avatars or signature lines change about 9:00am tomorrow MST.



Rich
DRSS

the second set is what happens when some bright fellow uses one of those laser bore sighters that is fit to the bore with o-rings you know the cheep ones and then leaves the o-ring in the barrell. and he walke away unharmed rem 700 used the action again without repair.

Looks like there might be more money in explosion proof actions than 2-bore's. Hmmmmm....

Only catastraphic thing that I have ever encountered was with a 1917 remington in 300winmag. I got it used. Headspace was good so I went to shoot it. That was a mistake, it scared the hell out of me.

What happened was whoever put the bbl on also installed the iron sites. When he drilled the site holes he drilled all the way through the bbl for the rear site.

I never did find the sites or screws and it peeled the bbl forward from the last screw hole for about an inch.

It was factory ammo but I'm sure there were other factors involved, I dont know.

It got my attention though.

I have some more burst barells in my colection of reminders not to be that guy. none of them are my mistake though.

for some of the stuff I see on a regular basis I think the schrapnell proof shooting helm and gloves would be a big seller

Crusher have any of you Texans had that problem with those Texas mud wasps in the barrel ??

dirt dobbers oh yeah you better look through it before you shoot it if it has been setting up for even a couple of days ,24 hours if its been sitting outside! saved my own ass on that one once.

Crusher- Thanks for the pics. Yup thats exactly what we have seen before from a muzzel obstruction.
Woodjack- Man thats a bad one! One of the worst and idea of an assignable cause?
I've also been told of an incident where a bullet shed its jacket in the bore, then a second round was fired and the bore obstruction blew the barrel. Point of least resistance.
Seems like that third locking lug on Mauser based actions is a darn good thing. So far only one reort ( Val Forget) was killed by a 6mm Winchester Lee sheding the bolt locking lugs and killing him instantly. (probably non-relevant to modern actions but a stern warning to the Krag/Lee crowd.-Rob

quote:

Robgunbuilder: I have examined more than one Argentine M98 mauser action with clearly set back action locking lugs

I know 2 people who spent alot of time and money building custom rifles on DWM actions who can support this. One utilized an 09 Argentine to make a 30-06, the other an 08 Brazilian in 425 Express. Personally I have not had it happen but have never used DWM actions.