While the folklore is that the 5.56X45 will over penetrate, the research shows that this is not correct. The FBI ballistics folks have found that for home defense or LE use inside a house, properly chosen 5.56X45 duty ammo is less likely to result in a through and through wound on an offender and far less likely to penetrate a typical household wall. (And this is OLD news - 20 years or more, IIRC.)

Such ammo is also likely to provide good ballistic performance in police work (FBI and most other feds are not cops, they are criminal investigators - different in many ways) against vehicles. In a shotgun, my academy taught the slug as primary, and buck as a specialized round with limited purpose. I adhere to that. The slugs you have chosen are recommended for serious work by the leading ballistics researcher (Doc Roberts, successor to Dr. Fackler). I would be confident with either. As I get older, the AR properly equipped (first quality such as DD/Colt/FN/BCM, with a really good light and Aimpoint) is more comfortable, but solid work can be done with slugs. (My shotgun is set up as much like the AR as possible - same sling; Surefire fore end; Aimpoint.)

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NHI, 10-8.