The M1 Carbine is the standard by which all PDWs are measured.

[stanc]

When did the design/testing begin for the weapon that became the M1? I think I've read 1938? We went to war essentially in December of 1941, so shouldn't credit be given for the way the rifle actually not only survived but entered the service so quickly with so many minds and eyes in other places?

Yes, absolutely credit should be given for getting the M1 carbine designed, developed, and fielded in such a very short timeframe. It was quite an achievement.

I'm inclined to agree on many points with Stan, but wonder about the bullet for the M1.

First thought is that the simple pressed cup round nose and straight walled case made ammunition manufacture as quick and easy as they can be made to be.

That's true, although I would think that the difference in difficulty of making spitzer vs round-nose bullets is too small to be of consequence, and would've been well worth the improvement in ballistic performance and terminal effects.

Second is that I wonder if I'm confused because the term M1 seems to be used for both the Garand and the Carbine making two topics into one...

That was my fault, for opining that the M1 carbine would never have been required if the M1 Garand had been developed as a lightweight assault rifle.

I hope it won't add to the confusion if I note that in addition to the M1 rifle and M1 carbine, there was also an M1 submachine gun and an M1 helmet.