re: Which AR caliber for deer hunting

.300 Blackout- 110 gr Barnes.

I bought it on a whim a few years ago for shits and grins- my little boy was 6 at the time.

I soon realized that he could handle the AR platform effectively because of the collapsible stock and low recoil. By 7 years old, he was decent enough on the bench that I thought he could hunt with it.

The stock mil-spec trigger was too heavy and creepy for a child, so I put a Timney drop-in in ours- other than that it's a totally stock M&P 15 with a 16" barrel.

He took his first deer with it on January 8th of this year and dropped her dead at the feeder- I believe the fit of the rifle, with a good trigger, short barrel for ease of handling, all contributed to him being able to make a good shot.

Yes, the .300 has limitations at range- but when is a kid really going to take a deer at greater than 150 yards anyway? His shot was 125, and I'm not comfortable with him going much longer than that.

Last week, I shot the gun off of sandbags with the above mentioned ammunition and pulled a 5/8" 3 shot group at 100 yards- I really believe in the round and the gun.