I'll bet you the cops' AR patrol rifles are marked for 5.56.
I can’t speak for everyone, but ours were very deliberately the *civilian* .223. Deliberate political move.
“I’ll bet you the cops’ AR patrol rifles are marked for 5.56.” [NorthMountain, post 44]
Let us hope you’re right.
MIL STD chambers are (a little) more generous in certain dimensions. And pressures for M855 rounds can exceed safe levels for civilian loadings. For safety reasons, it is recommended that M855 not be fired in rifles marked “223 Rem”.
Ruger has always maintained that its Mini-14 is safe with any 223 or 5.56mm factory loading.
Oh I know the answer to this!
In our state (MA) they use the smith and Wesson MP15. It’s a .223 cartridge. They use them because at one time S&W was a state industry; most former military could pick it up and use it effectively with little training; and they are inexpensive.
I don’t know about other communities...but that is standard in most MA Police Departments.