this is the best bore sighter on the market. I have used other less expensive laser sighters. they are limited in use.with thesite laser you can print out targets for any yardage you want to sight in yor scope at depending on the ballistic info you put in and it will tell you how far to set up your target in front of the barrel to sight in your scope for the yardage youwant . it also has other useful features. this is the same laser that the u s army-us navy -the us marine corps. use. there must be a reason . the site lite is easy to use-takes out the guess work and saves a lot of money I researched other laser bore sighters and I purchased site lite. oh!! you can also call the co. and they will also help you if you need assistance. note: I noticed in some of the other reviews, they complain about the "o" rings. if you follow the instructions and lube them with silicun or Vaseline, no problems

SiteLite SL-500This review is about the SL-500 used to sight in two semi-auto pistols with laser sights - a Sig Saur P239 semi-auto pistol with a 3.6 inch barrel and a Sig Saur P320 semi-auto pistol with a 3.9 inch barrel.These weapons are for personal defense, and therefore the range for sighting in is much shorter than for rifles which are used at much longer ranges.The SiteLite boresights are of excellent quality and will produce professional results for rifles if the instructions included with them are followed. SiteLite has three available models at different prices. All three produce the same result if you can see the laser dot on the target. The difference in the three units is the power of the laser and the batteries. The lowest priced unit is very satisfactory for sighting in work at personal defense distances if done indoors. I chose the SL-500 because it uses the same battery as my laser sight and tactical flashlight. I wanted to keep my battery supply simple.As described in the unit instructions, an O-ring installed on a screw-in adapter is used for different calibers. I find that installing the proper O-ring isn’t easy, and I suspect that it can be easily damaged. For those reasons, I suggest that once the proper O-ring is installed correctly for a particular caliber, it never be taken off again. SiteLite does that for .22 and .30 caliber. If you have multiple caliber requirements, I suggest you obtain a separate adapter for each different caliber and keep its O-Ring installed permanently.SiteLite claims the units to be the most accurate ones available. I don’t doubt that, but don’t know how to prove or disprove that claim. But I don’t think that projecting the bore sight line more accurately than others is the most important issue. The most important issue is REPEATABILITY. That is, the boresight should project the bore line of sight at exactly the same angle every time it is installed on the firearm.That is hard to determine with rifle scopes and pistol iron sights, but very simple with a pistol laser:1. Align the laser dot with the SiteLite dot at the sight in range.2. Remove the SiteLite from the firearm.3. Reinstall the SiteLite to the firearm and check the two dot alignments at the sight in range4. If they align properly, the SiteLite has repeated its projection. If not, there is a problem.I have done this exercise several times over a period of several days and some shooting sessions. The SiteLite has always repeated perfectly. There will be more about this a little later.Before getting the SiteLite SL-500, I was using the Bushnell Boresighter. After a lot of research and experimenting, I was able to get accurate results from the Bushnell, but to get those accurate results I had to make adjustments to the Bushnell each time it was reinserted into the barrel. The problem with the adjustment procedure is that it is a “by your visual sight” adjustment, and a very small error has a large effect. If you can get through that stuff, the Bushnell will work fine – just much slower.SiteLite has excellent tools and instructions for work with rifles and scopes mounted on top of the rifle, but almost nothing about pistols and lasers mounted under the barrel. Their great software app for scopes is useless for short ranges and laser sights under the barrel. Here’s how to do it with a laser sight.1. Make sure the firearm is unloaded.2. Put the pistol in a firm support such as a vice, aimed at a target at the sight in distance – 20 feet in my case. Align the laser sight dot with the SiteLite dot using the laser sight adjustment screws.3. Go to the range with a target. Install the target, making it completely level – this is important. Use a level.4. Steady the pistol as much as possible. Use a pistol vice suitable for firing if available – it’s not available to me. If a vice isn’t available, use sandbags and make such to make the pistol secure and as removed as far as possible from any movement introduced by your human hold and trigger control.5. Align the laser dot on the bull’s eye on the target, and fire a three shot group. If you don’t have a small group, you have done something wrong.6. In rare cases, your group will be within the 10 ring, but most times likely not. Don’t be alarmed, there are many variable in this exercise, and we’ll try to correct for them. The main thing is to get a small group with the laser dot on the bull’s eye. Label this target “Firearm Id, Sight In.” You will use many times again.7. Take the target home and attach it to a wall, making sure it is level – most important – use a level.8. Make sure that the pistol is unloaded.9. Secure the pistol firmly in place at the sight in distance. Attach the SiteLite to the barrel and align it with the target bull’s eye. The laser sight dot should also be aligned on the SiteLite dot. If not, there’s a problem.10. Move the LASER SIGHT DOT to the center of the target group with the laser sight adjustment screws. You’re done. Your next shot at the range at the sight in distance with the pistol firmly secured should be in the ten-ring and maybe even cut the bull’s eye – mine has.I hope you can see why repeatability is so critical. It is much more important than accuracy. Repeatability is required if you are able to make any judgements about the results.Final Thoughts:1. You must do this for every pistol. The first target group from the P320 was low 1.5 inches. The P239 first group was 1.5 inches high.2. You must do it for each different cartridge you shoot. I shot five different cartridges from three manufacturers. Each of the five loads required different sight in adjustments. The moral is to try to zero in on what you want to shoot.3. Save your “Firearm Id, Sight In.” target. Check it often with SiteLite and laser sight dot at the sight in range. The laser sight dot should still be centered on that group. That will tell you if the laser sight or anything else has changed. I don’t know any other way to keep check on your laser sighting system without firing a shot.Good Luck!Wil

This is the bore sighter to Own. I’ve had several and this is my favorite tool for rifles. It’s dead simple on accurate and if you don’t shoot the gun after sighting it you’ll be dead accurate when you do. Worth the money. You’ll wonder why you’ve never had this before.

I've had multiple laser bore sighters throughout the years but none that are built with precision and high quality materials. This thing is solid. I figured I'd stop spending money on less expensive lasers and just upgrade to the best there is. This is replacing my LaserLyte that decided to quit on me a few times now. In comparison... well... there isn't one. When holding the SiteLite you know this thing isn't going to break easily. The housing is heavy duty and feels solid in your hand. The green laser penetrates better in the sun and that was one major problem I had with the LaserLyte. The instructions are easy to follow and has all calibers you'll ever need.There is one thing I will point out which most will say here and anywhere you may read reviews. LUBRICATE your O-Rings before inserting the laser into the muzzle. If you switch weapons, LUBRICATE again. I made the mistake of not lubricating the O-Rings when I switched from my SCAR to my Sig and damaged the O-Rings. So now I make it a practice of lubricating every time it goes into a new weapon. I thought I didn't need to since I had lubricated them on the first rifle. Rule of thumb, always do it.I admitted my mistake with the company and requested an invoice to purchase some new O-Rings. They wouldn't take my money and instead offered to replace them for free. It was my mistake yet they insisted on making it right. You rarely find that level of customer service so they'll have a loyal customer for as long as the company seizes to exist. It's a small gesture but still something worth noting.

This is by far 10x better than the cheap boresighter I had before. Customer service with Site Lite is fantastic. Comes with everything you'd need. My only gripe is that even the green laser is impossible to see at 100yrds in daylight. Still a really great and accurate product.