Parallax in rifle scopes is the result of your eye being 2 to 3 inches higher than rifle barrel. If rifle scopes were not able to be adjusted to compensate for this, every shot would be 2 to 3 inches higher than the target. Rifle scope manufacturers recognize this challenge and on higher-powered scopes, 12x or greater, they include an adjustment to correct parallax. Once adjusted, the scope should provide accurate sighting. It is a good idea to check this adjustment from time to time.
Place your rifle on a supporting stand, shooting rest or on a sandbag. Use these aids to assist you in keeping the rifle as steady as possible.
Set up a standard target at 100 yards.
Aim the rifle towards the target and adjust the parallax ring on your scope to reflect the distance you are shooting.
Look through the scope with the eye you normally aim with and adjust the rifle position until the cross-hairs are in the middle of the target. Move your eye position up and down and from left to right, observing to see if the reticle moves across the target.
Adjust the parallax ring slightly and repeat the previous eye movements; once you observe the cross-hairs are not shifting when you move your eye, you have adjusted the for parallax at that distance.
Fire three to five shots and evaluate the accuracy based on the grouping of the shots you fired. Provided you aim in the same position, they all should be in a tight group.
- Once you have corrected the parallax on your scope for this distance you can use a white grease pencil to mark the position on the scope's adjustment, allowing for a quicker adjustment in the future.
- old soldier 9 image by Paul Moore from Fotolia.com