Stealthpine Tactics reviews the CVLIFE Rechargeable Magnetic Bore-Sight, highlighting its key features: a long-lasting rechargeable battery, a pre-centered green laser for accurate sighting from 15 to 100 yards, 16 numbered adapters for various calibers, an arbor for enhanced stability in larger barrels, and a highly visible green laser effective in diverse lighting conditions.
Moondog Industries reviews the Wolfroad Green Laser Bore Sighter that allows for quick and accurate resetting of any sights with sighting range between 50 to 100 yards... "The Wolfroad Laser Bore Sighter kit exceeded my expectations. The product was provided to me by VIPHiker, which produces the product under the Wolfroad and VIPHiker brands."
If you're having a hard time zeroing in your sight, you may just want to try a laser boresighter. All you have to is mount the bore sighter to your gun's muzzle and adjust your sight to where the laser dot is. The Bushnell version is available right now at Get Reload for US$28.99 and includes arbors for .22 to .50 rifles as well as 20 and 12 gauge shotguns. So you can use this for real steel weapons as well, not only airsoft.