The big difference between the M1923 sling and the M1(simple web sling) is that the M1923 makes an excellent shooting sling - just like the leather M1907 - providing solid support as a shooting platform when "slung up" properly, and greater accuracy potential. The M1 could not be used as a shooting sling in combat - you have to take it off the rifle and reverse the clip to use it that way, and it is still a poor substitute for either the M1923 or the M1907, overall - much less versatile. The M1923 was designed to replace the M1907 - lighter, cheaper and without the problems that come with leather that decays pretty easily - cracking, stretching when wet, etc. CC