What was the technical reason for going from 30-03 to 30-06?

[PhillipM]

If logistics was such an issue why did they invent the .30 carbine?

[RCS]

Maybe, they should have just used the old 35 WSL instead of development of the old 32 WSL into the 30 M1 carbine cartridge

photos show the 35 WSL with a 351 dia bullet at 150 grs, it is in a carbine magazine too.
you would not have the velocity of the 30 cal 110 gr bullet - but you would think that a 35 cal bullet at 150/160 grs would be a better choice ?

[Maury Krupp]

When the order to stop work on the .276 M1 Rifle was issued the M1 Carbine, the mechanization of the Army, the motorization of its logistics system, and the german's game-changing tactics of 1939-40 were all still nearly a decade away. The country was in the middle of The Great Depression too.

The idea to introduce a completely new cartridge for a single weapon in the Army's inventory was a non-starter for anyone who saw The Big Picture as it was in 1932. Especially when that cartridge was of questionable and certainly unproven combat effectiveness.

Maury

[KeithNyst]

30-03 vs 30-06
It is my understanding that with the 150 grain M1906 bullet loaded into the 30-03 case, the space between the ogive of the bullet and the rifling was deemed to be to great and it was felt that the ‘jump’ would cause accuracy problems. The solution was to set the M1903 barrel back two threads, which would correct the space problem (I thought that this distance was called ‘lede’ but cannot confirm it.) When the barrel was set back, the 30-03 case neck was too long; therefore the case was shortened to accommodate the new chamber. This is discussed briefly in HATCHERS NOTEBOOK.
.

Thanks Cosine26. That is exactly the technical feedback I was looking for. Odd isn't it ... based on your info, the 30-06, one of the best cartridges ever, came about due to a practical, mechanical modification of the M1903 30-03 so that it could fire 150gr spitzers accurately ... not a "from a ground up" new cartridge design whatsoever.

[John Beard]

Seasons' Greetings!

The decision to shorten the case, adopt the 150-grain spitzer bullet, shorten the barrel, and re-chamber the rifles was actually a single consolidated decision based on testing and evaluation, not a series of separate decisions. It didn't cost any more to optimize the cartridge than to optimize the rifle to shoot it. So Ordnance reasoned that it was cost-effective to do both at the same time.

The argument that the barrels were shortened and re-chambered to restore accuracy doesn't appear to "hold water." A far more compelling argument is that the barrels were shortened and re-chambered to reduce gas blow-by.

Hope this helps. Happy New Year!

J.B.

[raymeketa]

After setting the barrel back in order to shorten the free bore, the case neck could have been left as it was and would have worked just fine with the new bullet. But, that long neck was not needed so they decided to shorten it too. This actually led to some additional expense because 30 million of the M1903 cartridges were broken down, the case necks shortened, and the cases re-loaded as M1906. That's why you will find many M1906 cartridges with headstamps dating before 1906. Collectors who are not aware of this think they have found a rarity when the get a M1906 cartridge with a 1905 headstamp.

The Cal .30 Carbine was designed to be a lightweight specialty rifle for use at distances under 300 yards. It was originally called the cal .30 SR (Short Rifle). The .32 SL (Self Loading) cartridge fit the bill exactly. The first ammunition loaded is headstamped W.R.A. 30 SL. Later ones were headstamped REM-UMC 3 SL and WESTERN 32 SLR. These are all collectable.

ray