[NorthMountain]

In our state (MA) they use the smith and Wesson MP15. It’s a .223 cartridge.

Is the weapon marked "5.56mm" or ".223 Rem"?

[Vermont Lt]

Actually, I was wrong. My M&P was marked .223....I figured they all were. But I just looked it up on the SW site and the ones the cops use is the M&P Sport, which is listed at 5.56. (I just went down to check mine out and it says .223. But mine is more than 10 years old.)

https://www.smith-wesson.com/product/m-p-15-sport-ii

I wonder when THAT changed.