If you are getting jammed up for a gun, I doubt the trooper will allow you to be hands-free to use your smartphone. You reach for your smartphone and you'll likely be told to keep your hands on the steering wheel.
I also doubt that he/she would attribute any credibility to some website you pulled up--for all the trooper knows, you could have written that site yourself for the very purpose of concealing the illegality of your rifle.
It's just my opinion, the best defense is to be cooperative, but knowledgeable . If you sound like you know your laws and give a quick historical/legislative info dump during the stop, you won't sound like an easy target.
Trooper: "This is an illegal AK-47, you can't have these"
You: "Actually sir, this is a Chinese Type 56--a later, but distinct variant of the AK-47. It was Federally banned from import in 1989 by executive order of George Bush Sr. Therefore, all domestic examples of the Type 56 predate the passage of the 1994 Federal Assault Weapons ban and the equivalently worded New York Assault Weapons ban. Because it existed in private ownership prior tot he passage of such legislation, it is given "preban," or grandfathered status by the law and perfectly legal to own."
You sound like you know what you're talking about, you didn't say "I know more than you" and you don't sound like you're gonna roll. If you have to look all the up on the ole' smart phone, you still can.