So I want to get into some semantics here. The first question is 1) What does "AR-15 Style" rifle mean, if anything? Is this just the language of the antis that doesn't really mean anything?
In my book, if it follows Eugene Stoner's AR-15 design, it IS an AR-15. I could get into the specifics of what constitutes that design, things like the buffer tube, separable upper and lower, etc, but I won't in this post.
As one example, I would consider the Smith and Wesson M&P 15 a specific brand and model of AR-15. But it IS an AR-15, not just "AR-15 style".
Secondly, which is more of an assertion that I want people to confirm or dispute, that an AR-15 includes an entire category of firearms.
For example in my book, the M4/M16 are specific models of AR-15, made to certain specs including barrel length and a select fire option. I wouldn't normally refer to an M4 or M16 as an AR-15 because of current restrictions I think of those as military/gov weapons and AR-15s as more of the civilian version. Further, because the barrel length and select fire option make a huge difference from a legal perspective it is an important distinction to remain on the right side of the law.
An M16/M4 is a specific type of AR-15, built to certain specs, and has a burst or auto option in addition to semi-auto. I would even consider an HK416 a type of AR-15, with the main difference being the piston. You could pop the upper off and put it on an AR-15 lower and it would work, and vice versa. In free states you could build out an AR-15 to the same specs as an M4, either via SBR route or pinned muzzle device, and the only real difference would be the select fire option.
Is there any point in calling some an "AR-15 style" rifle rather than just calling it an AR-15? Does it make sense to think of an M16/M4/HK416 as a type of AR-15?