I have just purchased a rifle that will be used mainly for punching holes in paper from100-500+ yrds, and occasionally hunting but from a blind so no worries about quick shots or being a stalking weapon, my thought was to put a swfa 12x or 16x on the gun what are sum of the drawbacks or experience you have had w similar setups?

I'm probably the wrong person to ask. I've just moved my two primary deer guns to fixed 7x scopes, and bought a fixed 10x for an antelope hunt in September. I do like lower powered scopes on my autoloaders for hog hunting where there's an opportunity to bag two or three animals at one go. I've pretty much switched to fixed power scopes for deer, etc., where it's all about one shot. The variables are nice for pigs where it can be either precision work or a shoot-out.

Well IMO I would never get a fixed power with that high of magnification but I can see where as a range only rifle that might be fine.

For hunting you can't beat a variable scope because you never know what conditions you might encounter.

Drawbacks of fixed high power are 1)decreased field of view, 2) decreased performance in low light conditions and 3)harder to hold crosshairs steady. These mostly apply to hunting and not benchrest situations.

Back in the day variables had drawbacks relating to reliability especially with heavy recoiling rifles but these days there really are no drawbacks to a variable as long as one buys good quality.

Yes! But old myths never seem to die....