I will soon be mounting a scope on my AR and on my .22.  A friend of mine told me I will need a boresighter, otherwise it will be trial and error and lots of wasted ammo.  Is this true?

I was looking at cheaper than dirt, and saw this Leupold Magnetic Boresighter (It's catalog #37315 on the Cheaper Than Dirt website).

From looking at the picture, I can't even begin to guess how this will help me sight in my rifles.

Or should I just skip the boresighter altogether?

Edit to add, my .22 has a stainless steel barrel.  Maybe a magnetic boresighter is not the way to go.

-Nick Viejo.

If you can peek through the barrel from the chamber end, a boresighter is not necessary.  

Looking through the barrel, line up the barrel so you can see the full bullseye at 50 yards or whatever.  Making sure to keep from moving the rifle, carefully adjust the crosshairs to match.  

This method has never failed to get me well on the paper at short ranges.  About a half dozen rounds should get you dialed in, then move the target further back by 25 or 50 yards and repeat the process.

I'm sure the Leupold works well (and it should work on stainless barrels) but I have had good results with the cheap $10 plastic Tasco boresighting kit.  Since it will get you on the paper as well as the Leupold, no reason to drop any more cash than you have to.

I just realized that if I take off the lower receiver and remove the bolt & charging handle from my AR I can peek down the bore no problem.

As for my .22, as cheap as that ammo is, I'm not going to buy a boresighter for that.  So I guess than answers my question.  Thanks.

I've never used or needed a bore sighter. I sight in initially at 25 yds (do a 3 shot group), and then adjust for windage/elevation. Remember that a scope that is 1/4 click at 100 yds (4 clicks/inch) is 1/16 clicks at 25 yds (16 clicks/inch) Once you get your 25 yd zero, then move it out to 100 and shoot. Also keep in mind that if your scope is dead on at 25, it will be tend to be high at 100. Shouldn't take you too many rounds to get sighted in...Hope this helps.

Boresighters suck.

Open your AR, lay it over a padded stool on the shooting bench (so you can lean over to look through the barrel without kneeling on the ground), then peek through the barrel, adjust the sights, and repeat until you are satisfied - this will get you on paper, then refine the sight adjustment by shooting.

If you are lucky, an optical boresighter can get you on a 4 foot square target at 50 yards; they suck.  You can hold the gun in your hands without a rest and boresight it better than the instrument.

I've mounted well over a dozen scopes. What I do is this, if I can bore sight it by removing the bolt I'll try my best. But, it's rather a simple process when at the range. All I do is shoot at 5 gal paint lids that sit on the burm. Someone spots me tells me how far off I am and I make adjustments, no more then a half dozen shots to get right on target.