This is according to who?
People that take courses.
The carbine course I did, there was no shooting at all past about 30 yards, except the last 5 minutes of the day when we all lined up and dumped every mag we had into the hillside that was covered in steel plates.
I used my 12 inch PWS for day one and half of day 2 with an Aimpoint PRO and it was awesome. Day two I switched to my backup rifle (16 inch AR) at lunch break just to give it a workout, it had a 1-4 on it. The 1-4 with it's set eye relief and narrower field of view was a lot slower and harder to use. Not impossible but the Aimpoint was far superior for the task at hand.
Variable power scopes are heavier and are more finicky about your eye being in the perfect spot which isn't always easy when doing positional shooting like modified prone with all your gear on.
And why would you want to add more weight to an already heavy rifle when you're going to be spending the whole day with it hanging off your neck. Sitting at a shooting table the variable optics are awesome but for bashing plates within 100 yards nothing beats a quality dot sight.
And has already been stated, why on earth would you do a carbine course with a 308? Heavier and more expensive to shoot. I went through nearly 500 rounds in two days, that's already expensive enough with 223. Plus the increased recoil which slows you down on your follow up shots.
Jack of all, master of none. CQB is definitely on the none side with a 308 AR with a variable power optic.
OP, Listen to mileageman, I know him personally and he knows what he's talking about through actual experience, not the usual mall ninja CGN advice that is typically floating around.
If you want to do a CQB course go buy a $500 AR off the EE and you'll have a much more enjoyable training course experience. There is no one rifle that can cover all bases which is why we are allowed to have more than one rifle, and if your wife won't "let" you, then it's time to get a new wife (I'm not kidding, is she your mother or your wife?).
For a CQB course you want the lightest rifle you can get and a light recoiling cartridge. You will be shooting a lot, so beating up your shoulder shooting 308 all day from a heavy rifle is not going to be fun.
A buddy of mine has a VX-R 3-9 firedot and it's a nice little scope and would be a good optic for hunting. Again though, would be terrible for a CQB course.
I have a Leupold Mark AR 3-9 on my non restricted ACR and it's very similar to the VX-R in clarity but the firedot would have been a great addition to it.
