I posted a wordy explainer on another thread. You’ve got variables like… short barrel or long(er) barrel? how much of a concern is over-penetration? likely engagement distance (across the room or across the field)? barrier-blind or not? fragmenting or expanding or tumbling?
I use 62gr 64gr Speer Gold Dots. Barrier-blind, expanding round. They also come in 75gr and 55gr flavors. These are fairly readily available and reasonably priced.
My other recommendation, especially for short barreled (pistol or SBR) ARs, AND you have a lot of concerns about over-penetration, is the Sierra Tipped Match King (TMK) loaded by Black Hills or Corbon (there may be others loading that projectile too). It’s a fragmenting round with a core that gets you sufficient penetration to reach vital parts.
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