Pistol Boresights

I recommend using a vise to hold the gun firmly in place for the entire zeroing, so that the "point of impact" revealed by the boresight - marked on a target paper in ink - can remain fixed, the battery can be removed, and the point of the adjustable gunsight can be adjusted (whether red dot or laser sight or barrel gunsight) to coincide with where the boresight was set. It fit perfectly the 38 special it was bought for. I thought it might also fit 9 mm, and even 380 cal - it does not. Strangely, the rim is undersized - the ejector of the revolver cylinder does not catch it to eject it - but I don't hold that against the company; the item works as advertised on what it was designed for. The laser was centered perfectly - straight down the center of the bore - for the 50' distance to the target I wanted: rotations of the boresight within the revolver cylinder produced no visible "circling" on the target. Battery life is not advertised to be long - I think it was to be <1hr of actual "laser on" time - so don't waste time. Take out the batteries when you've learned what adjustments need to be made, replace them only when you are ready to actually verify, then remove them again. It's all easy enough.

I bought the 9mm version. I used it to adjust the iron and red dot sights on a 9mm carbine at 25 yards. The laser is only so bright, so you're either going to have to do this indoors, or outdoors on a less then bright sunny day. My unit came with 2 AG5 batteries. It will also accept 3 AG3 batteries. There is no on/off switch, when the batteries are in, the unit is on. I suggest you take them out when you're done. I had mine running for about 45 minutes on the batteries that it came with without noticing any change in the lasers brightness. After sighting in the iron sights at 25 yards, I experimented by rotating the boresight in the bore 90 degrees at a time to see if the laser was still aligned with my sights. I noticed no difference at that distance. My red dot is mounted on an American Defense quick detach mount. It was interesting and educational to use the laser to sight in the red dot. After my initial sighting in, I used my hand to flex and twist the sight on it's mount while it was attached to the rail of my gun. Guess what? It was clear I needed to tighten my mount! Then I used the laser to see just how well the red dot would hold zero when repeatedly removed and replaced on the weapon. Again, at 25 yards, I couldn't tell a difference. Finally, as I had done with the iron sights, I rotated the boresight 90 degrees in the bore, rechecking it each time against the red dot sight. Everything looked good! After all that, I switched to live ammo to check my efforts. I was off about half an inch high to the right. Fantastic results as far as I'm concerned! I'll sort out the rest at the range. I consider what I paid for this device money well spent for what I've used it for so far. Mine was a tad tight in the bore, even after cleaning the bore carefully and applying a VERY light coat of oil, I still had to use a pair of needle nose pliers to carefully extract it each time I removed it. I don't consider this an issue, just passing along my experience. EDIT: April 10, 2016 - Just a quick note on batteries, The second time I took this thing out to use it, the original AG5 batteries it came with were dead. The laser came on when I put them in but before I could use it, it sputtered out. I had bought a package of 10 Maxell AG3 batteries at the same time I ordered this boresight so I put in 3 of them. They lasted 10 minutes at best! I don't know exactly what to make of this information. Are two AG5s inherently better then three AG3s? Are the Maxells I bought just old or crappy? This much I can tell you, you gotta work quick to get anything done in 10 minutes...

Bought the laser bore sighter for 9mm. Pass this one up. Typical Sightmark QA. Build quality is shoddy, sighter gets jammed in the chamber, requiring a non-marring rod to pop it out. Tried using it, adjusted my red dot, popped it out. For fun, I reinserted the sighter. Off again. Readjusted my red dot. Removed and reinserted again. Off again. Obviously, the laser is off-center out of the box. Returned. Don’t waste your money, just buy a Site-Lite and call it a day. Yes, it’s more expensive. It is also much more reliable, better built, and yields more accurate results.

I bought this bore sight to sight in my new green laser. It worked good to "generally" get the green dot in the right area. You will still need to actually fire some live ammo to do the final adjustments on your laser. Laser bore sights are good, but nothing compares to actually putting some lead down range. Like others have stated in other reviews, if you un-chamber the bore sight and then re-chamber the bore sight, your red dot WILL be off a little bit. At 21 feet, mine was off by 3" on an indoor wall target. So what I ended up doing was to actually do multiple "sights" on the wall target from 21 feet. I would sight in the green laser aligning it with the red bore sight laser, then mark on the target with a black marker the exact point it touched (helps to have a second person to mark the black dots), then un-chamber and re-chamber the bore sight and repeat this 5 times. I ended up getting the green laser and red bore sight laser within 1" no matter where in the barrel the red bore sight was. And now, take it to the range and fine tune your green laser. I gave this bore sight a 4 star rating because of the inconsistantcies in the laser position. This tells me the red laser is not perfectly inline with your gun barrel. This bore sight is pre set from the factory and can not be adjusted. It is close, but it is not spot on. For the price, I guess I can't complain too much! I do recommend this laser, but if you want one that is more precise, you are going to have to fork over a lot more cash. CPS

These work great. Let’s be honest here, stop buying the super cheap ones and hope they work. I had to buy 2 other ones before this one because they didn’t fit right or the laser was junk. 100% recommend other the other brands.

I used this to zero in my pic rail mounted laser sight for my XDM ELITE OSP 9MM. I originally had my rail mounted laser sight zero'd to my iron sights. At 20' the lateral adjustment required was extremely small to align with this bore sight. I have yet to actually go to the range and do a proper on paper zero. When getting this laser bore sight (LBS) into my barrel, I thought I could slide it into my magazine, insert the mag into the Harwell, then operate the slide gently to insert the LBS into the barrel. The LBS was too long for that. I couldn't get the magazine more than an inch into the magwell. So, I locked the slide back, pointed the barrel down, and through the ejector port dropped the LBS into the barrel, then gently released the slide to gently seat the LBS into place. Got my laser dots to align perfectly at 20 ft. Lockung my slide back, the LBS wouldn't shake out. Went to the kitchen and grabbed a clean plastic drinking straw and pushed it in through the muzzle end of the barrel and was able to unseat the LBS with a firm push. After the LBS was removed I put it back in again to confirm the LBS was perfectly on axis in alignment. It was. Wash rinse repeat. Perfect alignment again Apparently I got a good unit. Some reviewers didn't, or perhaps they damaged theirs in the barrel seating process. Who knows? Anyway, it worked exactly as advertised. I would say its a precisely manufactured product. I recommend and would definitely buy again.

I purchased a new Taurus model 66, 4" barrel 357magnum from a brick and mortar gun store in Arizona. Either someone tightened down the sight adjuster screws at the gun store, at the factory or they were never adjusted to start with at the factory, but the result could have been disastrous. At 7 yards it hit 16" low and 12" to the left of center of target. I have several other sizes of Boresight lasers, but not one for the 357mag/38special. I received this one the next day from Amazon. It was slightly sloppy in the chamber, but I did as another reviewer suggested - I put one wrap of Scotch tape (with NO overlap) around the boresight cartridge and it then fit perfectly. Sighting it in was then about a 15 second process. Now the gun shoots right dead center on target as it should have from the factory.

First of all, I think that Sightmark Boresights are well made quality products & if that was all you had to be concerned with, then this would be a 5 star review. I have 3 other boresights in 380, 9mm & 45 Auto that I have been very happy with, so I ordered the 40 S&W without too much research. If i had read more reviews, I would have been aware of some of the issues with Glocks. Anyway, here are the problems that I experienced. #1: The laser would always point high & to the right. This is a result of the ejector impacting the boresight & causing it to skew in that direction when the slide is closed. I think that there are other guns besides the Glock that have this issue & that sightmark is probably aware of it, but I couldn't find any warnings on their site that it should be a consideration before ordering. I could have returned the boresight for a refund, but I'm kinda stubborn & I decided that I could find a way to make it work & I did. The solution was to file away enough metal from one side of the end of the boresight to clear the ejector which I did & that took care of the ejector issue. This required some care because you need to leave a large enough smooth flat face on the boresight to mate with the slide when it is forward. The end of the boresight where the ejector was hitting had a diameter of 0.327". I filed a flat on one side & removed about 0.037" which just clears the ejector. Once I did that and inserted the boresight with the flat facing the ejector, the laser stayed centered when the slide was closed. Once the ejector issue was resolved, I tackled the 2nd problem. The Glock & other guns have loose tolerances that increase reliability & also may decrease accuracy somewhat. The Diameter of a 40 S&W cartridge is about 0.420". The chamber on my G27 has a diameter of about 0.428" . The boresight diameter for the chamber section is the same as that 40 S&W at about 0.42". That makes for a loose fit for the boresight & could cause some minor inaccuracy. Realistically, it could be probably ignored, but I like to solve problems (even it it really doesn't matter), so I had some very thin (0.003") aluminum tape & I cut a strip & wound it 360° around the barrel of the boresight to increase the diameter to 0.428" & a nice snug fit in the chamber. I realize that not everyone will want to do all this, but it was fun for me & now I have a boresight that works just great. So to recap. 5 stars for the quality product & 1 star for ease of use, with a 3 star result.