At 150 yds the drop of a 223 centered at 100 or 200 is negligible. I have not heard if there was a scope? Probably not because even the worse shooter at that range is going to hit. Consider that Oswald with a bolt action was able to get off rounds at Kennedy in a moving car and hit (supposedly). God was definitely with Trump, and us, here.
BTW, he seems to have been sufficiently aware to not aim for center mass as Trump wears body armor, not that it would be 100% effective without a ballistic shield for a rifle.
Snipers in a gound level floor of a building looking out the windows. Now I have heard everything. “hey Gomer, there looks like a guy over there with a rifle” Bo responds, “is he wearing Camo?” “No”, “then don’t worry about it, he does not fit the profile”. But call it in and have another donut.
Looked like he was wearing a tan / grey type of camo