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17 Cards in this Set
- Front
- Back
Mean point of impact (MPI) |
The centre of a group of shots |
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Extreme spread (ES) |
Distance between the outside of the two most distant shot holes. The measurement is from outside to outside of the shot holes |
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Correct zero position (CZP) |
Is the technically correct location for the mean point of impact of a zeroed weapon. It differs from the point of aim when the sight setting does not reflect the true range |
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Estimated scoring area (ESA) |
The ESA estimates a firer's grouping capacity and is the area formed by a circle centred in the middle of the target adjusted for range |
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Permissible variation (PV) |
The acceptable amount of error remaining between the MPI of a zeroed weapon and the CZP |
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Calculation for PV |
ES divided by 4 |
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4 marksmanship principles |
The fires shooting position and hold must be firm enough to support the weapon The weapon is naturally aligned toward the target without any undue effort or strain on the part of the firer. The aim must be correct The shot is released and followed through with minimum disturbance to the firers position or weapon alignment |
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Why the group is formed |
1 when several shots are fired at the same AIMING mark, they will not strike the same place but will form a PATTERN on the target called a GROUP. |
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Causes of variation between shots |
A. Weapon and ammunition. Wet AMMUNITION, variances in manufacture of the WEAPON, and other factors B. Climatic conditions. Wind heat LIGHT and rain will all effect the round and weapon in some way C. Application of marksmanship principles. Where these principles are not adhered to the GROUP will be larger |
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What is a group |
We define a group as a PATTERN formed by a series of shots not less than THREE fired consecutively at the same point of AIM applying the MARKSMANSHIP principles |
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Grouping capacity (GC) |
Grouping capacity is a firer's ability to produce groups of a consistent size |
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Split group |
Change in body postion Change in focus Different POA |
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Wide group |
Dwelling in the aim For sight not Central in aperture for each shot Crosshair not centred on aiming mark for each shot Shutting eyes on firing |
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Vertical group |
Poor breath control Change in eye relief Butt slipping in shoulder |
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High left group |
Bracing no follow through Poor trigger operation Butt slipping in shoulder |
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Low right group |
Flinching Jerking the trigger Left hand influence |
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Diagonal group |
Head not upright Twisting pistol grip Rifle canted Inconsistent master hand control |