It's not a M1909. Nor it is a M1917. The 1909 has a much longer extractor rod knob, and it also would have a M1909 butt stamping. If it chambers a .45 Colt, it would necessarily have been re-chambered for it, or else have a .45 Colt New Service cylinder. Does the .45 Colt case chamber completely, all the way down to the rim? Simplest answer is that it is an early .45 Colt New Service with 1917 grips. What's the SN (inside the crane)?