Dropped the ball on this one.

what would actually happen if you fired a round like a .270 in a 30-06 chambered rifle,
Click to expand...

What actually happens is the case expands to fit the chamber (to the limits of its ability) and the bullet goes wobbling down the barrel.

When you fire a (shorter) round with a larger caliber bullet than the bore, the same things happens, but the bullet is squeezed down in the barrel, resulting in a huge pressure spike. Sometimes enough to damage, or even destroy the gun.

.270 in an 06 is a very close fit comparatively speaking. Cases are nearly identical.

There are other combinations that fill fit and fire, some intentionally and well, (.38 SPL in .357 Mag, etc.) some that work, poorly (.270 in 06, .308 in 06, etc) and some that are dangerous.

As long as the round fits in the chamber well enough that the action can be closed, and something holds the case head against the bolt face when the gun is fired, the round will go off! What happens after that can be good, ok, meh, or OMG!!! depending on what round your firing in what chamber! And, whatever it is, it will happen, instantly!

One really needs to keep an eye on these things! :D
 
I recall athread awhile back....

When you fire a (shorter) round with a larger caliber bullet than the bore, the same things happens, but the bullet is squeezed down in the barrel, resulting in a huge pressure spike. Sometimes enough to damage, or even destroy the gun.

.270 in an 06 is a very close fit comparatively speaking. Cases are nearly identical.

There are other combinations that fill fit and fire, some intentionally and well, (.38 SPL in .357 Mag, etc.) some that work, poorly (.270 in 06, .308 in 06, etc) and some that are dangerous.

As long as the round fits in the chamber well enough that the action can be closed, and something holds the case head against the bolt face when the gun is fired, the round will go off! What happens after that can be good, ok, meh, or OMG!!! depending on what round your firing in what chamber! And, whatever it is, it will happen, instantly!
Click to expand...



http://thefiringline.com/forums/showthread.php?t=481895
 
Yikes! Interesting thread you brought up jimbob.

One really needs to keep an eye on these things!
Click to expand...

Oh don't worry 44 AMP, I'll pay close attention to that stuff! :D I'll try not to fire a .308 in a .270 anytime soon either.
 
While I'm not going to test it (I don't even have a .270), and I don't recommend you test it, either, a .308Win in a .270 chamber might be one of those combinations that strain the gun but generally don't ruin it. Might spoil your barrel though. A 7mm-08 in your .270, you might not even see that. And a .243 in a .270 should only have an unusual recoil and report.

I do, however, shudder to think what might be the result if you slipped a .358 Win into your .270! :eek:

USUALLY, the .308 family of cases will fire in 06 family chambers. Usually. This is because the .308 case shoulder is a snug (sometimes crush) fit in the 06 chamber at that point, when both the chamber and the case are in spec. this is usually enough to "wedge" the shorter case in the longer chamber so the firing pin fires it. But not always. Sometimes the case is just a little too far forward for the firing pin to reach properly. This sometimes happens with semi auto actions, which slam the case into the chamber with some force.
(also, a lot of ammo will be slightly under spec diameter at the actual shoulder, and will go in the bigger chamber a little too deeply to be fired)

UNLESS the extractor engages the case rim. If the extractor is engaged with the case rim, the fit of the shorter case in the chamber might be a moot point. In a CRF rifle (like the Mauser 98 or Win M70-pre64) if the round is fed from the magazine, this is absolutely going to happen.
 
"it was some nations mortars"

Yep.

The Edgar Brandt company of France developed a series of mortars in the 1920s and 1930s in 60 and 81mm.

Variations of the basic design were used by the United States, France, China, Italy, Roumania, Germany, Japan, and others either purchased mortars from Brandt or purchased licenses to make their own.

These mortars were based on the British Stokes Mortar from World War I, which was also 81mm bore diameter.

The Soviet 82mm variation of the Brandt design was adopted because the Soviets inherited 82mm mortars from the World War I Czarist army.


The whole "they could use our ammo, but we couldn't used theirs" is such bullcrap when it comes to small arms.

The closest that comes to being true is with the Japanese 7.7 Arisaka round, which was liberally based on the British .303 round.

There were actually 3 variants of the 7.7 round -- a rimless round for rifles, a semi-rimmed version for use in Type 89 machine guns, and a rimmed version (basically a copy of the .303) used exclusively by the Imperial Japanese Navy for Type 97 aircraft machine guns.
 
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