I was having a totally unrelated conversation with a guy at the range and he made a comment about not wanting to shoot with "that" with NVGs on, "that" being my little Savage 308 with an acupoint.
I didn't think about it at the time because it wasn't what we were actually talking about,  but now it's bugging me.
Why couldn't I shoot that rifle as is with a PVS14 on at night?

If you're talking about it mounted to the 308 I don't think it's rated for it.

No, on a helmet.

Why ccouldn't/shouldnt I just pick up the rifle and shoot it normally?

He might have been referring to the difficulty of lining up the head mounted 14 with the small fov on a scope or the huge muzzle flash. NVGs work best with a laser or red dot scope.

It's technically possible,  but the LOP is going to be way wrong, you'll need to focus the pvs14 a lot closer than normal, and the scope cuts down so much light that you need either extra IR or a full moon.

You'll lose so much light through the scope you likely won't see anything through it. For night vision with a variable power day optic you want a "clip on" like a PVS-27 or PVS-30. Then it would work fine.

I wouldn't want to risk an expensive scope smacking into an expensive PVS14 under recoil.

I've used a helmet-mounted PVS14 behind an ACOG on a turret-mounted M249 SAW at pre-mob training ranges. In one scenario, we were supposed to be engaging illuminated pop up targets at various ranges while dealing with a disabled vehicle. We were supposed to be walking our fire into the targets in our lane via tracers, but I figured if I had a PVS14 and an ACOG why not use it?

So i just cupped the PVS14 to the back of the TA31 and put the chevron on the target. Instead of walking the machine gun into the target, it was just a quick burst for every target and down they went. My team leader was impressed and I continued to use that technique throughout the rest of the training, but afterwards I realized I had actually ended up limiting the amount of fun trigger time I could have gotten.

That said, a machine gun and a precision rifle aren't exactly the same thing and neither is a turret-mounted 5.56 weapon vs a 308 on a bipod in terms of recoil...