And odds are good that you'll never ever use it. Lots of manufacturers leaving that part off these days. Was more necessary in the days of the M16 in the jungles of Vietnam where dirt and grim could leave a guy without a working rifle. Now they handle the dirt and grim much better than they ever did before.
Agreed on never needing it. Worse than an appendix (adds complexity and cost at negative return) .
As for Nam, question always was, what good does it do to force a round into a gummed up chamber? The answer is it does not.
So, the correct answer is you should never use it. You might get one shot.
Ok, I will say, if one shot will save your life, go for it. Otherwise......