NIB original Colt 3x20 effective range?

[NAVY SEABEE 303]

I have been gifted an NIB original Colt 3x20 scope (USA model) for my AR, What should I expect as a realistic effective range for this thing. The little book it came with says 500 yards. does anyone have any experience with one of these?

It looks like this one, sorry i didn't take my own pic.

http://www.simpsonltd.com/product_info.php?products_id=19731

 

[Vaarok]

Optics have no bearing on effective range, they just let you see the target more clearly. If you can hit with irons at 500, the scope will just make it easier.

 

[Andrew Wyatt]

the BDC on the scope goes to 500, so, the answer you're looking for is 500.

 

[NAVY SEABEE 303]

Sorry about the "effective rang" wording my bad. Does anyone have any experience with one of these? I am kind looking for feedback from someone who has or is using one.