By Mark V. Lonsdale, STTU
Team Global Precision – Derek, Paul & Mark
One of the (many) potential mistakes made in ELR shooting is over compensating for a miss and then missing again but in the opposite direction. This can result from making a full-value adjustment instead of a half-value hold or adjustment
For the purpose of this discussion, we will be engaging a steel plate at 2,000 yards and making the the assumption that the shooter, rifle, and ammo are capable of at least MOA accuracy at that distance (approx 20″ group at 2,000 yards).
With a steel plate that is roughly 24″ x 40″ this is what a 20″ group would look like. Keep in mind that the shooter has no way of predicting where a shot will fall within that group. It could be on the very left side of the group or very right side of the group, or high or low.
Now the shooter’s first shot is off the right edge, possibly because of an unseen wind shift from 9 o’clock, and the spotter calls for an adjustment and says, “Aim left edge”
Shooter aims center but first shot misses to the right — however, the shooter does not realize that the shot was already on the far right edge of the group. Had it been centered or left of center, the shot would have hit the plate. This is the random nature of large groups at longer ranges.
Shooter makes a full-value adjustment to the left edge of the target
The problem with this full-value adjustment is that the shooter is thinking of the shot as a single point of aim rather than the center of a 20″ group.
By using a full-value adjustment, the shooter risks missing off the left edge since over half the group could be left of the point of aim.
The solution is to use a half-value adjustment to the sights or hold. The goal being to keep the entire random nature of the grouping within the steel target.
By making a half-value adjustment, the shooter has increased the probability of a second round impact on the steel target.
Try this the next time you are hunting steel at extreme long ranges, and remember, carry a mental image of the size of your group at the target distance. The other important requirement is a good spotting scope and spotter. If he or she can’t see your misses, there is no way of knowing how to adjust sights or point of aim.
.416 Barrett built on a BAT action and Bartlein barrel in a McMillan Beast-2 stock.