What caliber do yall think is best? I'm thinking about changing one of my ARs up to a different caliber. Something that is kid friendly but maybe a little more stout than a 223. Maybe a .223 is fine, just seems a tad small. Shots would only be 20 to 50 yards.

I use 300 Blackout. I've killed a few deer, but it doesn't have the knockdown power of the long action rifle. The plus is its short and compact, and light on recoil.

I think it’ll be fine at those distances.
I would use a 60-75Gr bullet that the rifle shoots well.

X2

I use 300blk and 6.5Grendel. If you are only shooting 100 yards or less then .223 has several good options to get it done. 300blk has options to do the same with around 30% more energy but you’ll have to find the right bullet.
7.62x39 is roughly the same as 300blk in supersonic loads but will require a special bolt and magazine.

AR10 .308 is the way!!! Don't have one? Doesn't everybody need a .30 caliber battle rifle?

223 is fine with the right bullet. My son killed his first deer with one. We used the federal Fusion bullets. They are bonded and don't come apart as easy. I would shoot Barnes or some kind of bonded bullet. If you want a different caliber look at the 350 legend Its awesome for deer and less recoil than a 243.

I have one in 7.62x39 in built with hogs in mind. Never shot a deer with it but I suspect it would work.

If hell bent on buying a new caliber. 300 blk out upper is the cheapest. If you want another gun, 308 AR 10 are dropping. Seen at PSA for $700

I use a 300blk. Killed a coyote at 189 yards, dropped in tracks. Shot a 174lb buck @ 100 yards that went 30yards. Shot a 168lb buck @ 110 yards and he went 10 yards. watched both go down. shooting winchester deer season xp150 gr. Its a powerful round inside 200 yards.

6.5 Grendel or 6mm ARC.

300 BO is my favorite, stay within 150 yards with 110-125 gr bullet.
That’s all I hog hunt with.

At those distances a 64-77gr 223 will work. My daughter started using a 6.5 Grendel when she was 10 and didn’t have a problem with it.

Many outfitters I have scanned recently have outlawed the use of AR's and state it plainly on their websites.
I'm not sure what type of problems have caused them to do this. None of the ones I saw made any mention
of caliber or why they have done it. Maybe someone here knows. FYI

Based on the results I saw on 200#+ deer in Iowa last year, 450 Bushmaster would be hard to beat. Thor's hammer

At 20-50 I'd be happy with a good 223 round but the 300 is easy to find and has a little more oomph I think while remaining gentle on the kiddos. The 350 Legend is a serious step up in short range power and not exactly a shoulder killer itself.

inside 300yds, 6.5 grendal. Thors hammer
129grn nosler long range. I love that round.

223 is plenty!

I've dropped a bunch of deer shooting eld-x handloads with my 223 ar

I have used the Grendel.