ELR Shooting & Half Value Adjustments

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).

Target 2 Group

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”

Target 3

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. 

Target 4

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.

Target 5

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.

Target 6

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.

END

Mark Lonsdale .416 Barrett

.416 Barrett built on a BAT action and Bartlein barrel in a McMillan Beast-2 stock. 

 

 

 

 

 

About Mark V

Dedicated shooter, seeker, traveler, teacher, trainer, educator
This entry was posted in 375 CheyTac, 416 Barrett, Barrett Firearms, Cutting Edge Bullets, ELR, Extreme Long Range Shooting, Mark Lonsdale, Peterson brass, Precision Rifle Shooting, Reloading, Rifle Shooting, STTU, Tactical Rifle Shooters, Team Global Precision. Bookmark the permalink.

4 Responses to ELR Shooting & Half Value Adjustments

  1. Craig Arnzen says:

    I don’t understand – why was the first impact zone right of the POA and the second was right on? I’m not sure I understand the logic in the first impact zone having an offset (like wind) but the second not having one.

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    • Mark V says:

      First shot was a center hold but wind or spin move the group to the right. The shooter then reads the miss as completely off the right side when it fact it was just the right edge of the group. The goal is to bring the entire group back onto the plate. Wind may again blow it right, but it will remain on the plate

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      • Craig Arnzen says:

        But the move he makes with POA is 1/2 the place when you cite the overcorrection. His kiss was caused by a miss on an environmental shift, as he went from center-hold to left edge.

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      • Mark V says:

        Most shooter’s first reaction when they miss off the right edge is to go to the left edge; when they should go half to the left

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