I am a believer that at the firing line, there are 2 ways to show the TO that M12's do not have a live round in the chamber: my old way that gives the same results & the Rule Book way. So at a local match I did a my way,one time, and knew I was a candidate for a SDG
* At the loading table put the bolt in battery on an empty chamber and then put the safe on - then load six
At the firing line released the safety, pulled the trigger and the loud 'click' was heard. Yes, I said - SDG? and after discussion with the TO and MD and the Rule Book, I got my SDG but this one time only ... I was allowed to finish the stage because the book had to be read for the exact wording
I grew up on Ithaca 37's and the safe was always engaged with an empty chamber before I loaded and went into the field or blind