Japanese change from 6.5mm to 7.7mm

[Snider shooter]

Military bullets are currently made to tumble when they hit causing greater wounding. As stated by others the 6.5 punched straight through. The 7.7 bullet was made to tumble on impact. This what they where trying to achieve by going to the larger round.

 

[green]

Military bullets are currently made to tumble when they hit causing greater wounding. As stated by others the 6.5 punched straight through. The 7.7 bullet was made to tumble on impact. This what they where trying to achieve by going to the larger round.

The 6.5 bt used by Japan from c1905 was a pointed spitzer of 139 gr weight.
During the 1920s the US and A of America Army conducted trials of .256" (6.5mm), .276" (7mm) and 30 cal M1906 and M1 ctgs. Live pigs and goats were shot to determine lethality. The most deadly was a .256" load which was very similar to the Japanese 6.5mm. The .276" was chosen due to its larger tracer potential.
The Japanese were looking for a longer range MMG and having extensive experience with the .303" (7.7mm) chose that calibre with a more modern case.
Note that all other nations using a 6.5 mm rifle ctg, Holland, Sweden, Norway, Italy adopted a larger calibre for MMG use.

 

[Joel]

Military bullets are currently made to tumble when they hit causing greater wounding. As stated by others the 6.5 punched straight through. The 7.7 bullet was made to tumble on impact. This what they where trying to achieve by going to the larger round.

Why not just make their 6.5mm bullets tumble then, and not complicate their supply/manufacturing situation during a war?

Assuming they flew a straight path I really don't see what damage any nation's larger caliber (other than the above noted 303 Brit) was going to do that turned a non-incapacitation into an incapacitation.

Without documentation/source material stating that...I don't really think its a solid case. What green (and others) suggest is much more reasonable.

 

[johnny1984]

I had read something as well about the effects of the no tumbling being part of their decision.

Allegedly they felt that the stopping power was lacking in the 6.5.

Military bullets are currently made to tumble when they hit causing greater wounding. As stated by others the 6.5 punched straight through. The 7.7 bullet was made to tumble on impact. This what they where trying to achieve by going to the larger round.

 

[Mumbles Marble Mouth]

Wrong thread

 

[Joel]

Would be really curious to read whatever that was johnny1984

Looking at cutaways of the 7.7mm ball round I don't see anything that looks like it was made to tumble or would tumble on impact. Looks like a very straightforward lead core in a jacket with no air pocket or wood or aluminum plug at the tip. Doesn't look unbalanced or like something that would lose stability on imact at all.

 

[Cottage Hill Bill]

The .303B round wasn't designed to tumble on impact, that was a by-product of design. The wood/aluminum tip was a result of getting the weight in the right place for stable flight and filling the hollow front portion of the jacket to prevent damage in handling.

 

[green]

The .303B round wasn't designed to tumble on impact, that was a by-product of design. The wood/aluminum tip was a result of getting the weight in the right place for stable flight and filling the hollow front portion of the jacket to prevent damage in handling.

Absolutely correct. Spitzer FMJ bts all tumble on impact not just .303" MkVII. The US Army noticed this when they first used the cal 30 M1906 ctg (150gr FMJ Spitzer )c1914 in Mexico. This is discussed well in "Hatchers Notebook".

 

[Joel]

Absolutely correct. Spitzer FMJ bts all tumble on impact not just .303" MkVII. The US Army noticed this when they first used the cal 30 M1906 ctg (150gr FMJ Spitzer )c1914 in Mexico. This is discussed well in "Hatchers Notebook".

Yeah? Huh...they don't all seem to in gel, or in game, at all. Perhaps they all do eventually, but some do so much sooner and more violently than others.

I didn't know the MkVII was not made with that in mind though. Thanks.