I say carry Chuck Norris.
Okay, to be more reasonable, carry the largest thing you are comfortable, reliable, and accurate enough with to feel you can trust your life to it. If you're comfortable with the Glock (like I was for almost 15 years until I discovered three of the greatest letters in the world, USP) then by all means, continue. Practice enough that you're beyond comfortable with it. If possible, find training facilities within a reasonable distance and get some formal familiarization and training. As the late Col. Cooper was so fond of saying, mindset is more important. Full Metal Jacket's Gunnery Sgt, Hartman also said it well: "You rifle is only a tool. It is a hard heart that kills."
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