The tip is blurry in your photo, but the overall shape looks right. I have a couple extra firing pins I ordered years ago in case I needed them, but I haven't so far. One AR has about 10,000 rounds through it on the original firing pin.

Any AR firing pin will work. It doesn't have to be S&W. I ordered mine from CDNN Sports. They were not expensive - I think about $3-$4 each at the time. Maybe a bit more now, though.

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Or something like that . . .