I am told that someone who works for the ATF went crazy when he saw this photo of a rare variant of an M1 Firing Device. I knew they were rare, but I didn’t know exactly how rare. Apparently even T13 grenades aren’t as rare as this M1A…something variant. So I was glad to hear that the fellow I sold them to was going to give this ATF person one for Christmas. (The speck of yellow paint on the thumb screw would seem to indicate that they are an earlier version of the standard M1, which would be in keeping with what this expert at the ATF said.
Is this known as the Combination Firing Device M1?
If I had any more I’d give you one because I just searched “Combination Firing Device M1” and found images and tech drawings of the same one. Thank you for identifying it. John