What would happen if you touched off a .308 in a .30-06 chamber?
- Thread starter philthygeezer
- Start date
If the extractor held the case firmly against the boltface, it is possible that nothing untoward would happen, apart from the case fireforming to fit the chamber. It is also possible that a casehead separation could occur, and this would be a bad thing.
This is the reason why the magazine spacer block is a really good idea in a M-1 rifle converted to .308.
This is the reason why the magazine spacer block is a really good idea in a M-1 rifle converted to .308.
Sorry Tiriaq, but it would likely blow the rifle apart, especially the stock.
The case has to hold the pressure. In this instance the 308 case is so much shorter than the 30-06, that the gas pressure would blow out all over the place, taking things like magazines and wood with it.
This is why it is practically impossible to get a 308 in a 30-06 chamber.
Other dangerous situations are a 300 Savage in a 30-06.
The case has to hold the pressure. In this instance the 308 case is so much shorter than the 30-06, that the gas pressure would blow out all over the place, taking things like magazines and wood with it.
This is why it is practically impossible to get a 308 in a 30-06 chamber.
Other dangerous situations are a 300 Savage in a 30-06.
I have heard of it happening, and resulting in a case with a straight wall and the beginning of a shoulder being ejected. I also read this story about a guy who inadvertently chambered a 308 in a 270
http://thedonovan.com/archives/2008/12/270_winchester.html
http://thedonovan.com/archives/2008/12/270_winchester.html
IF there were a casehead separation, close enough to the head of the case, release of pressure could result in a shattered stock.
The shorter case fired in the longer chamber would result in lower pressure.
Remember the conversion sleeves to allow the .308 to be fired in .30-06 M-1 chambers? No problem getting the .308 cartridge to chamber.
My .308 snap cap fits fine in a .30-06 chamber. Hence the question.
I wonder if the bullet even gets partway into the narrow end. Would it even go down the barrel every time?
I get shudders just talking about this kind of stuff.
Tried it. The firing pin drives the .308 snap cap forward into the chamber. I'll bet the primer would detonate if it was a live round. In a bolt gun, the claw extractor would help the round detonate.
I have seen a 308 case that was fired from a 30-06, and this is exactly what happened.
The case in question is still sitting on the counter at Shooters Den in Sudbury as a conversation piece.
There are different possibilities which could result from what is basically a case of grossly excessive headspace:
1. Cartridge moves foreward, cushions the strike, misfire occurs.
2. Extractor holds the cartridge enough that the primer fires, pressure expands case, case stretches until casehead seats against boltface.
a) Case fireforms to chamber, resulting in the odd fireformed shape mentionned above.
b) Case is stretched beyond its limits, and casehead separation occurs.
i) Separation is far enough foreward that gas seal is maintained.
ii) Separation is close to the head, there is a loss of obturation, high pressure gas is released.
If 2 b) ii) occurs, you better be firing a Remington 700.
1. Cartridge moves foreward, cushions the strike, misfire occurs.
2. Extractor holds the cartridge enough that the primer fires, pressure expands case, case stretches until casehead seats against boltface.
a) Case fireforms to chamber, resulting in the odd fireformed shape mentionned above.
b) Case is stretched beyond its limits, and casehead separation occurs.
i) Separation is far enough foreward that gas seal is maintained.
ii) Separation is close to the head, there is a loss of obturation, high pressure gas is released.
If 2 b) ii) occurs, you better be firing a Remington 700.
- Location
- Somewhere on the Hudson Bay Coast
Personally I make a point of using the correct ammunition in my rifles, but lets consider for a moment what might happen if a .308 was fired in a .30/06 chamber. First, the head size of the .308 and the '06 are the same, so with a M-700 type bolt face or a CRF bolt face, the round would be held in place and in line with the center of the bore. Thus, there should be no misalignment between the bullet and bore. The tricky part has to do with the rapidity by which the .308 brass forms a gas seal in the chamber. If the gas is able to get between the brass and the chamber wall, nothing good can come of that. However, if the cartridge expands and contains the gas, you might only observe lower than anticipated velocity. What you get away with in opne situation you might not in another. So who has a rifle they want to donate for testing?
Guy that pulled the trigger on that one must have shat his pants.
About 3 or 4 times a year, I find examples of cases that show they were fired in the wrong chamber at our range here. Most common one, I believe is 7mm Rem Mag in 300 Win Mag. You end up with a super short necked 300 case, and usually no harm done. I have also seen the 308 in 30-06 case...I believe I have one at home that I picked up. Looks like no harm done in this case, but the potential for a kaboom is definitely there. Another one was the 303 Savage in a 303 British. The guy fired 3 of these before he clued in. 300 Win mag in a 300 Weatherby is another I have seen a couple of times. 6.5 M-S in a 6.5x55 chamber...case ruptured and damaged a fine old Swede. People are either really foolish, or they completely fail to pay attention. Regards, Eagleye.
"...the conversion sleeves to allow the .308 to be fired in .30-06 M-1..." When they came out upon extraction, the U.S. Boat People got the oddly shaped case described by 220Swifty. No damage to the rifles. Mind you, you have to work at damaging an M1 Rifle.
"...chambered a 308 in a 270..." That'd be worse. That 31 thou difference in bullet diameter can cause all kinds of horrible things to happen.
"...Interchangeable barrels can look remarkably alike!..." That's why they're stamped with the chambering.
"...chambered a 308 in a 270..." That'd be worse. That 31 thou difference in bullet diameter can cause all kinds of horrible things to happen.
"...Interchangeable barrels can look remarkably alike!..." That's why they're stamped with the chambering.
That was Matt. (mattimoose here on cgn) He did it on purpose, to prove that it could be done safely. IIRC, he said that according to Hatcher's Notebook, 308 (7.62 nato) was designed specifically so that it could be fired from a 30-06 chamber
http://
I just took this at Shooters Den
The two in the middle are 30-06, flanked by the 308 cases I just mentioned, with two unfired 308 on the ends.
You can see that the fired cases have blown out to fit the 30-06 chamber, with just a bit of shoulder, which supposedly seals the chamber, and allows the 308 to be fired somewhat accurately, and without losing all of its chamber pressure.
Battle of the Bulge match in CFB Shilo, Brandon. Group of us used to go there every year. It was a "fun" shoot, around Dec 10 or so and It could get real ccccold. Almost everyone was shooting garands and one year we noticed lots of straight walled .308's laying around. Mentioned it in the clubhouse afterwards and finally someone owned up to the fact that they had grabbed the wrong ammo that morning and never noticed untill after 5 o 6 enblocs that they couldn't seem to hit anything. Other than that nothing untoward happened while shooting them.
I was present when one of the members here intentionally fired a bloc full of 308 in a 30-06 Garand. Every round fed, fired, and extracted routinely, and the cases were simply blown out with a very slight shoulder formed at the mouth.
Consequently, I tried chambering a few factory 308 rounds in several 30-06 rifles. Because the shoulder on the 308 is so much larger than on the 30-06, the 308 would barely chamber in two of the rifles, and chambered easily in one. It was a sort of squeeze headspacing, if you understand what I mean.
So, I fired a round off in each of the tight rifles, and got the same result as the Garand. Then, fired a couple in the looser rifle with the same results. Not a problem with any of the rifles.
Finally, just for giggles, I fired a 358 Win in a 35 Whelen and got the same result
Ted
Consequently, I tried chambering a few factory 308 rounds in several 30-06 rifles. Because the shoulder on the 308 is so much larger than on the 30-06, the 308 would barely chamber in two of the rifles, and chambered easily in one. It was a sort of squeeze headspacing, if you understand what I mean.
So, I fired a round off in each of the tight rifles, and got the same result as the Garand. Then, fired a couple in the looser rifle with the same results. Not a problem with any of the rifles.
Finally, just for giggles, I fired a 358 Win in a 35 Whelen and got the same result
Ted
A guy came into my friends gunsmith shop with a straight walled 308 case. He was wondering if my friend could give him an explanation for this. After looking at the rifle (I don't remember what it was) the man was advised it was chambered in 30-06. This guy said he had been shooting 308 in it ever since he bought it years ago. Apparently he used it for hunting and had used it succesfully on several animals so he must have been getting some sort of reasonable accuracy. Never did hear from him how it performed after switching to 30-06.
