It's a simple device. Attach the correctly sized arbor, clear the weapon, stick the gizmo down the muzzle, adjust sights, remove, go to the range.

It does the job well. There's no appreciable change in the dot's position when you rotate it within the barrel, so I'm certain the laser is aligned.

Personally, I have not run into the issue where the switch fails, and I hope I never do. But if I do, I can rely on the other reviewer's handy tip to fix it.

It comes with a handful of arbors designed to fit every caliber the folks at Bushnell could think of. Unfortunately, they don't all fit snugly. Not to worry! Use the arbor that's slightly smaller than than the bore. You can use Scotch tape as a shim. Wrap a layer around the arbor, test the fit, and apply more tape if necessary.

This is the cheapest bore-sighter I could find and I'm thrilled it works as well as it does. It cost twice this price at the big sporting goods stores. Granted, those same stores offer free bore-sighting, but sometimes I don't have the time to go to the store or the patience to deal with the smug sales reps. This is much more convenient and not a whole lot more expensive.

You just need to be prepared to do a little McGuyver-ing. (Yes, it's officially a verb now.)

great little piece of gear, tuned right up to my 6.8 and saved me a buck a round to get it on paper. I didn't think the little screws were all that hard to put in, but the switch is easily turned on in storage I guess, mine was dead in about a day. The batt. tray right in the middle is very easily removed. Most of the other reviews are on point though use the smaller rear piece and thread out to your calibur. I would advise this as a great alternative to a high dollar set-up, or a trip to the gun shop every time! big thumbs up guys!!

.....enough to make it not worth buying. I read how I can pop off the front cover and adjust it, but that would void the warranty. It'll get you on the paper if that's all you want. Spend the extra money on a good one, although I heard the chamber type aren't that good because they don't fit tight. I tried to get the cover off to adjust the screws inside but couldn't get it off and didn't want to break it. If anyone has a suggestion, reply to this review and I'll be notified.

I recently purchased three Marlin bolt-action .22 rifles -- one each for me, daughter, and son. Son owns 20 acres where we can shoot but he's 2 hours away. I mounted a scope on each of the rifles then bought this Bushnell boresighter.

My neighbor's workshop is about 60 yards away from mine across flat ground. Just after sundown I used this device to boresight all three rifles. It was simple -- screwed the .22-cal adapter into the end of the boresighter; jammed it down the muzzle of the rifle; put the rifle in a bench stand on the concrete porch of my workshop; aimed the rifle at my neighbor's workshop and turned on the boresighter; looked through the scope; there was a red dot on my neighbor's workshop wall 60 yards away; fiddled with the UP/DOWN LEFT/RIGHT knobs on the scope to put the crosshairs on the red dot and that was it. Maybe took five minutes and most of the time was spent screwing the adaptor onto the end of the boresighter.

Yesterday took the rifles to my son's place where we set up a bench rest then put paper targets at 50 yards and 100 yards. At 50 yards all three rifles shot within the rings with the first three-round shot group. Two more groups and we were tearing up the bull. Nine rounds per rifle to zero the sights. All rifles were dead on at 100 yards also, with slight Kentucky windage correction for elevation.

Negatives. Instructions could use a better illustration. The plastic adapters should be marked with their caliber. The on-off switch is dinky and can be turned on by sliding the boresighter into its little case. I put a piece of masking tape over the switch to protect it and keep it turned off. This device is lightweight and not exacly "robust." The device probably won't stand up to a lot of rough handling -- it should last me a lifetime because I don't throw my things around but some folks delight in treating their gear as roughly as possible.

If you're a big-time shooter who is all the time mounting and un-mounting scopes, fiddling around with various rifles, and the like, then, don't buy this thing -- check out Midway and get yourself a big bucks CNC machined boresight device complete with machined adapters for various calibers. If you're like I am -- one rifle every ten years or so -- this thing will do what you need it to do.

the whole thing is cheaply made and very badly designed, the threads are easy to strip, the arbors are easy to lose, the screws are allen heads and not long enough for long use/durability. The cheap plastic switch falls off with repeated use.

and the laser reaches out at most under ideal conditions 25 yards tops.

over all for half the price I'd suggest getting one and it will save an extra round or two sighting in, but over all it is a cheaply made gimmick that won't last long enough for oyu to find out it doesn't work that well.
Skip this and buy the better bushnell boresighter with expandable metal arbors because you get what you pay for.