It works best to approach the magnet base to the muzzle end ...
Puts me on target at 25 yards each time I've used it. Take the time to center the magnet as close to center of the barrel as possible. It works best to approach the magnet base to the muzzle end of the barrel, from a 90 degree angle, slowly letting it come to rest flat. For me, it made it easier to center the magnet on the first try with a little film of gun oil to help prevent any possible scratches. Make sure base of magnet and barrel end are clean. For first use, I would compare it to placing a quarter over the top of a dime. Centering the magnet as close as possible to the muzzle end. I just eye balled it best I can. That's all you need to do. It works as advertised. You don't need to center this device perfectly. You don't need a lot of little parts that get worn out or lost. This laser (green) projects perfect on target at 25 yards and farther depending on light conditions. makes it simple to put the scope's crosshairs on the green dot. I read a lot of reviews before purchasing this particular Bore Sighter. What convinced me to go with this one included the Issues from other type tools that insert into the muzzle that users then complained about replacing or losing guides and rubber gaskets made me consider this one over that other type. Considering the price, it seemed to be the best option for me. Price, Great Reviews, and it functions as advertised. It puts you on target quickly, and you don't lose or need to replace little necessary parts. The little case is perfect for instrument and battery storage.
amazon reviews