SightmarkCenterfire Boresight with Red Laser

I have four of the Sightmark laser boresights - the 12 gauge, 9mm, 7.62x39mm, and .223.I had used a Bushnell laser boresight before getting this set of chamber loaded laser boresights. The Bushnell is the kind that you stick into the muzzle end of the gun, fitted with an arbor matched to the barrel size. The problem with this device was that the arbors never fit quite right - they were always either too tight or too loose, plus you had to try to seat the body of the boresight in the center of the opening of the barrel (or muzzle brake) in order to properly align the center axis of the boresight with the center axis of the barrel. This rarely if ever happened just right as the slightest tilt in the seating of this boresight in the barrel would take it off the center axis so that rotating the laser would cause the laser light to mark out a small circle that was several MOA in diameter rather than being dead centered. Ugh.Of course with these chamber loaded laser boresights, there is also the potential for the lasers to be mis-aligned off the center axis. Plus there is the potential for the boresight to not fit the chamber properly. The key is to find a brand that has a measure of quality control so that you aren't stuck with these problems.I read through a lot of reviews before deciding on Sightmark. It is definitely not the cheapest out there. There are so many different brands and generic versions of these chamber loaded laser boresights now that almost look alike, with many much cheaper than the Sightmark. However, it was clear from reading the reviews that as the prices went down, so did the quality control. Several of these cheaper brands came with complaints that the lasers were not aligned to the center axis (resulting in the laser painting a circle as it rotates in the chamber) or that they did not fit properly in the chambers and so would either get stuck or wiggle.I have this theory that the really cheap laser boresights must be factory seconds or some such.I considered the Osprey line with the adjustable arbors, which saves money by allowing you to use one laser bore sight for different calibers. But, the reviews indicated that hassling with arbors would have an effect on accuracy and reliability.I almost got the Firefield, which seemed to have a similar number of decent reviews. Ultimately I decided against it because the entire line is made of an aluminum shell, and I think the brass shell of the Sightmark will hold up better.It should be noted, however, that the 12 gauge Sitemark is made out of aluminum, unlike the others, and is only painted a brass color.The biggest complaint against all of these laser boresighters are the frequent DOA batteries and poor battery life. The Sightmarks all come with alkaline button cell batteries. The small caliber ones (9mm, 7.62mm, .223) come with two AG5 batteries while the 12 gauge came with three AG13 (LR44) batteries.To get you all confused, the printed information on the back of the packaging for the 7.62mm and .223 says you can use 3 AG3 batteries in place of the 2 AG5 batteries (since the AG3 is a thinner battery with the same 7.9mm diameter), while the printed info for the 12 gauge says you can use 2 AG5 or 3 AG13 batteries. This is flat out incorrect since 2 AG5 batteries are too small to fit into the 12 gauge Sightmark battery chamber.Confused? Go to wikipedia and look up the article "List of battery sizes". Scroll down to the section titled "Silver oxide and alkaline cells". The table lists all the different names for each battery, their dimensions, and their mAh power rating. Note how the silver oxide batteries contain 1-1/2 to two times as much energy as the alkaline batteries.So the key is to go out and get some silver oxide button batteries, size SG5 for the AG5 powered Sightmarks and SG13 for the AG13 powered lasers. And don't go to your nearest retail store, since that will cost you an arm and a leg. Google shop for these batteries online. I found two Made in China "brands" one called Vinnic and another by Chung Pak Battery Works which were pretty cheap. The names aren't important, since I'm sure they will change rapidly. Just remember to get some silver oxide batteries online at the same time you are getting these Sightmark bore sights.How well did these Sightmarks work? The very first time I used one (the 7.62x39mm), I plugged in the included AG5 alkaline batteries and the resulting laser light was exceedingly weak. My initial reaction was that this was a bad laser. Then I remembered the silver oxide batteries I had gotten. When I switched out the batteries, the laser suddenly glowed brightly. Later, when this set of silver batteries finally wore down, the laser light faded again. That's a sign to change batteries.The larger AG13 alkaline batteries for the 12gauge shotgun boresight worked reasonably well and are still working as of this writing. Not surprising, since these batteries pack a lot more energy than the small AG5 batteries.As many have noted, the Sightmarks do not have an on-off switch. Once the batteries are screwed in the laser light is on! This is just as well, since the bore sights have to flush fit inside the chamber of the barrel and endure having the bolt and firing pin slammed into them. But you do have to have a plan of action ready so as to not run down your batteries. With one pair of SG5 silver oxide batteries, I was able to adjust the sights for about four guns, each taking about 5-10 minutes. So I am guesstimating a battery life of about 30 minutes with a fresh pair of SG5 silver batteries (the Sightmark packaging claims up to an hour of battery life - hah!).All of the Sightmarks have fit in well, none have gotten stuck (so far), and none have had off-center lasers.These chamber loaded Sightmark boresighters make it easy to dial in a scope, and for fixed sights, they help confirm the aim points. They are much better than the muzzle loaded bore sights, although the total cost is a lot more since they are ammo caliber specific.

CONSTRUCTION: The laser body is made of sturdy brass, nicely finished, and with an excellent fit for the firearm caliber. The version I purchased is for a .308 Win caliber rifle. The laser is perfectly aligned with the barrel axis, so it won't make fringes once it's manually placed in the chamber. If you follow the instructions that came with the laser you'll zero in your rifle in no time...and without spending a lot of rounds in the process. (A note to semi-auto firearm users, such as M1As: after manually inserting the sight laser into the chamber, do NOT slam the action as you would with a normal round - this will damage the laser. Instead, SLOWLY advance the action until it closes the breech. This note is in the user's manual, too, but it won't hurt to note it twice.)ACCESSORIES: The laser comes with a small holster for storage, made of ballistic nylon. The holster is large enough to store the laser, its batteries and the user's manual. {However, it is small enough to lose it, too. ;-) }. It comes with a set of two button-size batteries (LR 754).Some things to note:- it's not a high-intensity laser. Therefore, you may have difficulty seeing the laser beam at 25 yards in the open on a very sunny day.- due to its size, the laser uses two button batteries (LR 754), and those don't last a long time. My recommendation is to keep the batteries in the provided pouch until ready to use, and to carry a spare set just in case.CONCLUSION: For what it was designed, it does an excellent job. I wish the laser intensity would be higher, or be of a different wavelength (color; e.g. green) for better visibility in bright, sunny light. I will definitely buy it again if I lose or damage it (I hope I won't), provided the company is still there if that happens.

Bought to sight in a red dot. Worked great to about 12 15 yards. Bought it to zero at 25 yards but can’t see the dot after 15 yards. It did get me on paper and close to where I was aiming. It made sighting in easier and used much less ammo to zero it. I’m giving it 4 stars because at this price I expected to see it at 25 yards.

I used this to sight in my .308 M1A rifle. I got a new Vortex scope and a Basset Machine mount for the holidays and took it out to the desert to get it sighted in. I couldn't even get it on paper, so I decided to quit wasting ammo and get a boresight.The Sightmark boresight came with batteries and simple instructions. I put the batteries in and the laser lit up. Once I got it chambered I matched up the laser dot with the reticle and that was it. I did it in the late afternoon so the laser dot would be bright. My aim point was about 20 yards. Of course, at the range I would have to adjust the elevation for shooting at 25 or 50 yards, but windage should be the same. Sure enough, I was on paper and had to adjust the elevation while the windage adjustment was minimal.In sum, this product worked perfectly to get my scope on paper. Some notes:1) There is no on\off switch; once you put the batteries in and screw on the cap the laser is on. You have to take the batteries out when you're done. They are tiny little things. I used the corner of a plastic sandwich bag and rolled them up in it, and it fit in one of the little pockets in the fabric case.2) Open the bolt and seat the boresight in the chamber as you would load a single bullet and don't let the bolt slam close as this would probably damage the boresight.3) This is a low power laser, so you're not going to be able to see it on a bright day at 50 yards. Probably not even at 25 yards. That means you need to use it indoors or at around dusk if you use it outside. Using it indoors will limit the distance you can set your elevation at, but the windage will not be affected.4) Boresights are not designed to set your scope for the bulls-eye. They help you get close enough that you're hitting your target, and you can go from there to get an exact adjustment.