Thread: Sighting in your hunting rifle

100m zero for everything centrefire, 50m zero for .22LR subsonics.

Sighting in 'an inch or twa eye at a undred yards' is the worst approach for today's world with good scopes (although relatively few and far between), rangefinders with ballistic calculators, ot just a better knowledge of how trajectories work in rifles.

The bullet 'falls' the second it exits the muzzle, due to gravity. Due to this, our sights be it iron or telescopic, must point downwards relative to the muzzle, so you raise the muzzle to aim at the chosen target.

Why a 100m or yard zero?

Most rifle cartridges (2,000 to 4,000 fps muzzle velocity) will be on a relatively constant path till this point, where they will begin to diverge due to ballistic differences (bullet speed and shape). Rifles ranging from about 2,500-3,200 fps will usually require 1 Miliradian or 3 MOA of 'dial' (elevation on sighting device) from a 100m zero to score a hit on a 6 inch target at 300m.

100m is also relatively isolated from factors such as wind deflection and possible muzzle velocity variations of ammo (extreme spread) influence, which would begin at 200 yards or meters. Also, who can judge the accuracy of a rifle that is zeroed to shoot above the target you are aiming at? Do you carry a tape measure to ensure it is always the same distance above your aiming point?

100m zero will mean an almost dead on aim for shots up to about 30m away. Much more usefull for up close shots that must be taken quickly, vs. an imaginary sotuation where the stag of a lifetime is stading 850m away, across a canyon on a perfectly calm day and facing perfectly broadside. The latter situation could still be handled with a good dial scope that zeroed for 100m and dialed in.