What size would a person have to be to comfortably handle a rifle like an AR?

my 13 yr old son uses his spikes in 3 gun

To say it has barely more recoil than a .22lr is not accurate, but it has the least of any common centerfire rifle round.

The difference in range and power between a .22lr and a centerfire rifle is enormous.

We had a female in one of my units who was 4'11" that could shoot the M-16 as well as many of the males. The good thing about the rifle is that all of the controls you will need to mess with are very close to where the pistol grip is.

She had much more of a problem with our 870s, having arms too short to pump it well.

Six-position adjustable stocks are pretty common on AR carbines these days. So stock fit shouldn't be an issue.

You need to be able to reach the trigger, safety selector and magazine release. All easy even with small hands... and I'm deliberately not mentioning the forward assist, I don't like 'em. Charging handle and bolt stop/release are support hand jobs- again, should be no problem. Left handed? See Stag for a lefty AR.

In short- shouldn't be any problem for you to handle an AR...

lpl

I'll concur with many of the others. Being around 5'8" myself with smaller hands, I handled my M16-A2 in the Army just fine. The only thing there was the fixed A2 stock, which I usually had to contort a bit(usually being more sideways then normal and tucking the stock underneath my LBE/LBV) to keep my nose to the charging handle. All the adjustable stocks I've handled since then have been just fine though, so if you can go that route there in NJ then that would be your best bet.
Also, welcome to the forum, you'll already notice that you can get some great tips here, you'll just have to wade through all the replies from people who read half of your original post and not one word more before they replied.

AR's are kosher New Jersey?

So what sort of size do you guys think a man would have to be in order to comfortably use a rifle like the AR?

I know of a 4-10 85# woman who can outshoot most men with an AR/M16.