Hmm - I'd always thought the .334 was the full length case with standard taper, just necked up.

so I checked one of my books.

According to J.J.Donnelly's book, it's 2.80", .050" shorter than normal .375 Length & has a .437" shoulder diameter with 39.09 degree shoulder angle. The shoulder is listed .010" smaller in diameter than the parent case. Interesting.