I've also noticed the no sights, when the gov gunned down the national guard unit in the previous season, they didn't have any sights either, and all these full auto M4's, I guess they think every swinging Richard in the Military carries a machine gun...
The grenade down the barrel of the tank would work if the breach was open. I guess they can't be accurate with everything, but it bothers me!
But even if the breach were not open, wouldn't the concussion break their eardrums and mess them up (the folks inside the tank)?