doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Barrels bursting

I personally have seen guns, some of the better names, with barrels that burst. My intent is not to pick on one brand or another, but to get opinions on what key factors might play a role in causeing barrels to burst.

Examples: Browning SP, bottom barrel let go a few inches ahead of the chamber. From looking at the gun, it was an earlier model and the looks were that it had been used a great deal.

Second is a K gun, fairly new but shot many thousands of rounds. The barrel burst right behind the chokes. It had never shot anything but target loads, a lot of factory. Lets use the assumption of no obstruction.

Since it is not likely high pressure necessarly, could lots of rounds work harden the steel to where it just gives out and fails?

What effect would low pressure vs high pressure have on the barrel steel.

Lenard

I've shot lots of rounds, fast in South America. The ends of the barrels would get white hot and no ill effects. Stuff happens?

See the new DGJ. Sherman Bell says bursts at the chamber are caused by overloaded shells and bursts further down the barrels are caused (generally) by obstructions. He gets into the details regarding thin polished barrels and their hazards. It is an essential read for anyone shooting old guns.

Burrard; A S Barnes US edition,copyright 1961, Volume III page 361;
""But let us return to the subject of pressure bursts.
It has been seen that the danger is greatest in the immediate neighbourhood of the breech. And it can now be stated definitely that a burst or smash caused by an excessive pressure must always occur in the immediate neighbourhood of the breech ; further, that such damage will either be a cracking of the action across the bar, or else the bursting of barrel in, or immediately in front of, the chamber.""
This was of course written prior to the 1961 US copyright date, so has been around at least 60yrs.

Miller, in your opinion, barring obstructions, will barrels split using low pressure loads, under 8000 psi or there abouts

It appears to me, that the continual flexing of a barrel, does have an effect on the steel. I am trying to understand how low pressure loads traveling at the same speed as high pressure loads, will effect the barrel over thousands of rounds. I understand the chamber pressure part of this but I am confused about how these barrels can split without obstructions.

Thanking you in advance.

Lenard

One thing that must be fully grasped here is that as normally used in high vs low pressure loads, we are almost always talking "Exclusively" of chamber pressure. A "low pressure" load ie low chamber pressure may or may not have a lower bbl pressure than a higher pressure load. "If" the same ballistics are acheived, ie for instance say 1 1/8oz shot @ 1200 fps, with one load @7,000 psi & another @ 9,000 psi then the higher pressured load would beyond a doubt have a lower pressure for the most of the rest of it's bbls length. The thing to remember here though is that this max variation is within a very short distance while the other is spread out over most of the bbl's length. Thus while we have this 2k psi variation within the first couple of inches of chamber, for the rest of the bbl pressure is likely less than 4-500 lbs. I really think that, with the possible exception of very heavy loads using a large amount of slow burning powder, the actual load has little affect on this type of burst. These loads would not necessarily show an excessive chamber pressure & would still peak within the chamber area but would maintain a slightly higher bbl pressure, though not one which would ordinarily be considered excessive or dangerous.

Llemke,a couple of years ago one of our club members had the end of one K gun barrel tube depart rather quickly. He readily admitted, after the fact, that he allowed the screw in choke to partially back out - can happen.

Thanks, guys. I have seen parts of a choke tube missing which I suspect was an out of round tube. Is it fair to say, that most of the guns that have split barrels, are mainly on the thinner side, even well within the recommended minimal thickness? I know I got to inspect the Superposed after the rupturing of the barrel and it was quite thin. Did not have any opportunity to measure the wall thickness though.

What is a lot of shells? I put at least 250,000 through a lighting super that I had to have Browning rebuild before I shot it much because it was off face. The gun is still shooting with the third owner .
bill

O hwell, topics like this make me wish I was 17 again. Would'a got me an engineering education and find out for myself. Can't help wondering, you know - when you see a fellow shooting modern 70mm shells through a pre-1914 gun with 65mm chambers, season after season, without any trouble except the barels are slightly off-face. Is this felow just lucky? Or when another fellow's brand new magnum semiauto goes burst for no apparent reason - is that fellow simply out of luck? Or should I believe a friend of my Dad's, who's a high-pressure pipelines expert - he says 8 out os 10 bursts are caused by hidden defects in the metal, which are enhanced by accumulated stress, and while the burst will probably coincide with a rise of pressure over everyday level (e.g. a slug or goose load), this pressure rise is simply a trigger, not a cause, of the burst.