They are the same since the Colt Delta Elite was the first gun chambered in 10mm Auto. Thus the moniker Auto Colt. This was before the 10mm was shortened to become the .40S&W. Now they are labeled the same since the die is interchangeable. I wouldn't buy the Auto Colt as they are probably old dies from the early 90s before the advent of the .40. Sorry for the confusion, Don.John, explain the difference. All the 10mm Colt searches I do lead back to 10mm Auto.
The 10mm Auto Colt is the same dimension as the modern 10mm. Yes, with the modern dies, the 40 and 10mm use the same die like the 38/357.So to avoid confusion, is the cartridge for the 10mm Auto colt longer than the 10mm, and the 10mm is longer than the .40 S&W but both the .40 S&W and the 10mm cartridges can use the same dies like 38/357?