What would happen if you touched off a .308 in a .30-06 chamber?

Decades ago I had the "pleasure" of firing a .308 Win cartridge in a Mauser bolt-action rifle chambered in .270 Win. It was a friend's rifle and I was firing ammunition he had loaded into the blind magazine.
Very loud blast, I got a faceful of gas. Having had experience with head wounds once before, once I recovered from the initial shock,
I asked my companions if my face was bleeding. (It wasn't). No facial wounds, thank goodness. Made me glad I was wearing eye protection and double hearing protection (plugs and muffs).
Exhaust gases venting from the action had plated small particles of brass on my glasses. (More modern rifle designs deal better with combustion gasses released by cartridge failures).
Ironically, my friend and his then-girlfriend (also an experienced shooter) had been shooting the same rifle earlier w/o eye protection.
The stock cracked at the wrist, releasable floor plate, spring and follower swept away and lost. High-speed swaged projectile hit the target :)
(.308 diameter swaged down to .270 diameter).
Bolt was frozen shut. We didn't learn until much later that the wrong ammunition had been fired in the rifle, after the owner got a report from the .270 Win
cartridge manufacturer on the rifle he sent them for examination. (I would guess the short cartridge case would be a giveaway one the mfgr got it open, since the headstamp
might have been ironed completely flat?)

My friend subsequently expressed surprise that .308 Win cartridges would fit in a .270 Win chamber and permit the action the close.
Learned something from that.

Let's be careful out there...
 
I have seen spent .308 cases that look like those in post #16 at my local range. So it does happen. I wouldn't try it though.
 
I have seen spent .308 cases that look like those in post #16 at my local range. So it does happen. I wouldn't try it though.

Ahhhhhhh, okay. I didn't look through all the posts and obviously never did any measuring or comparing. It looks like the neck is missing, I left it at that, I learned something today. :)
 
Years ago, when I was young(er) and stupid(er), I had too many guns on the bench and wound up firing a .308 in a .300WinMag. Knew I had made a booboo just by the sound and feel. The case was split, the shot was out of the group but still on the paper, and the rifle appeared undamaged. I had it checked by a 'smith before using it again, and he confirmed that it was fine, and said that there was no real reason to suspect damage. He suggested I avoid the practice in the future. I still own and use that rifle. To this day, and hopefully for the rest of my life, I consider that the dumbest firearms-related blunder I have ever pulled.
 
BASG, quote this post to see how to use the image tags. ;)
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i have fired a 308 out of a 30 06. got a nicely formed straight wall case. i didn't even relise until i extracted the case. what i did notice it was about 6 inches outside the group but still on paper.. it was in a rem 700. i have learned to close my ammo boxes except the one i'm using.
 
I have read that part of the design requirement of the 308 (for the military) was that if it were accidentally chambered in the 30'06 rifle, it should not cause a safety concern.

Consequently, I have read about people who have done so and the 308 case simply stretches far enough forward to form a seal and nothing horrible happens.

I would think that this would work better with a mauser type action which holds the cartridge firmly against the bolt face. In a push feed action, the firing pin might not set off the primer or, even if it does, it might push the case forward which would then be pushed back again during ignition and a gas seal may not be formed.

All in all, not a great idea but certainly not the worst. Firing a 308 in a 270 or 280rem or similar would be far, far worse.

Edit: just read thread: yep.
 
Some rifles will tolerate more pressure than others.

I recall reading of several intrepids who in the face of many theories, actually tested several rifles to destruction. One such test involved running a very much larger chamber reamer (so the oversize bullet would chamber) into the 7.7mm Japanese Arisaka. IIRC, he was shooting .35 or similar size bullets. That action held up really well, and the very much larger than theoretically possible bullets, went down said bore without much fuss.

Been lots of guys out there have proved that a better dummy comes along every time something gets dummy proofed.


Cheers
Trev
 
I have read that part of the design requirement of the 308 (for the military) was that if it were accidentally chambered in the 30'06 rifle, it should not cause a safety concern.

Perhaps the design of the service rifles involved at the time helped in this as well.
 
It appears that the question of .308 winchester in a .30-06 has been well flogged. It has been done, but shouldn't be.
There are some misconceptions about other cases. The .300 Winchester Magnum (belted), uses the same case head, belt and headspacing as the .257Weatherby magnum, .270 Weatherby Magnum, .300 Weatherby Magnum, .308 Norma Magnum, 7mm Remington Magnum, .338 Winchester Magnum, as well as .300 H&H, and .375 H&H.
There is no danger in firing a shorter, or smaller calibre, in the above, in a .300 Winchester magnum.
Accuracy will be poor if you shoot a .257, .270, 7mm in the .300, but all of those cases are shorter than the .300 Winchester magnum.
Now, forcing a .338 into a .300, or 7mm, will be very bad, and a couple of the anecdotes reinforce that.
All very nice and academic, but use the right ammo, and if they are similar, keep only one of the bench at one time. Just like reloaders should only keep one container out at a time.
It is a whole different game with the Winchester Short Magnums and the like, none of them should be anywhere near a belted chamber.
 
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.

would it not be a problem with the bullet being so far away from rifle lands??? bullet is going to line right up???
 
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