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.