[coondogger]

I just bought a Tasco red dot 1x42 sight. Very inexpensive but fine for my purposes. I attached it to the rail of my ar-15 and went to zero it in at the range. I fired three shots at a 50 yard target which left the paper unblemished. I moved up to 25 yards. Nada. What's going on?
At factory settings the thing should at least be somewhere on the paper (8 x 11"). Is there something I'm missing here (other than the target)?

[Glocky]

OK, remember the dot is about 3 or so inches above the bore so it should be shooting high.
My method for sighting in a new scope
Place a brightly colored dot/white paper circle/etc about 2" or so at about 25 yards away, take the upper off and situate the upper so you can see down the bore and when you see the dot, or whatever you picked to sight at through the bore, try to fix/hold the upper still (holler for help) and simply adjust your red dor or crosshairs to the same object. That should get you on paper for finite adjustment.
Or,
Put up a larger paper or cardboard 3ft x 3ft and have a 2-3" pc of white paper taped in the center, at 25 yards aim at center and fire one off. If it is on the cardboard, fix your rifle in position, I use a shooting vise, aim at the same spot you did when you fired that 1 shot, then simply adjust the red dotover to the bullet hole you just made.
Then the next shot will be on your bullseye or center of whatever you used, if slightly off, adjust by clicks till you are on, this usually takes up to 5 shots max.:banghead:

[Hunterdad]

Go get it bore sighted and that should get you on paper. Once your on paper you can dial it in from there.

[OpticsPlanet]

Go cheap: Pull the upper off, sight through the barrel until you're on target, then adjust the optic. you should be on paper.

Or, invest in an inexpensive laser bore sight.

This does .22 to .50BMG, and all your friends will want to steal it.
http://images1.opticsplanet.com/180-180-ffffff/opplanet-bushnell-magnetic-boresighter-740001c.jpg

http://www.opticsplanet.net/bushnell-magnetic-boresighter-740001c.html

Mark H.