With a free-floating firing pin like the AR-15, snap caps would still be recommended though, right?
Exactly how much dry firing practice are you going to do with an AR-15 though? Seriously, it's not that big of a deal, but if your OCD requires, make up some snap caps, or buy some. Regardless, it's not going to hurt your AR-15 to dry fire it, but that is a personal choice.
I dry fire my AR only when I get done cleaning it and am doing a function check, so to me it's not worth the cost or time to make snap caps.