NRA Probationary Course Unit 8 The Rifle Sights Compiled by Dave Burton
NRA Probationary Course Unit 8 Introduces: Minutes of Angle Vernier Scales Elevation & Wind Settings Different types of sighting system
Elevation And Distance When the rifle is close to the target the bullet hits the centre providing the sights are correctly set to the bore
Elevation And Distance But: - further away, the bullet drops due to gravity and air resistance
Elevation And Distance To hit the target the front of the barrel must be raised The longer the range, the more the barrel must be raised
ELEVATION • The further the distance from firer to target, the greater the angle ‘x’ has to be. trajectory x Firer l‘x’ Target is the angle measured on the sight. Target
ELEVATION • Only a small change of angle is needed at the rifle end to make a big difference at the target end • The angle is measured in MINUTES of angle - (one minute is 1/60 of a degree) • At 100 yards, changing the sight by 1 minute, changes the fall of shot on the target by 1 inch
Minutes Of Angle A minute of angle is: The adjustment of the REARSIGHT that will cause the POINT OF IMPACT to move 1 Inch per 100 yards
ELEVATION • Therefore: Distance 1 minute at the target is: 100 yd 1” 200 yd 2” 300 yd etc. 3”
ELEVATION 3 inches 2 inches 1 Minute 1 inch 100 yds 200 yds 300 yds The graph above is the change in line of sight as you raise the rearsight. Line of sight is a straight line. A bullet’s trajectory is a curve as the bullet drops.
Approx elevation To Allow For Bullet Drop Over Set Distances CHANGE (yards) RISE BETWEEN RANGES (minutes) 100 - 200 2. 0 200 - 300 2. 5 300 - 400 3. 0 400 - 500 3. 5 500 - 600 4. 0
Elevation This gives us the standard rises between ranges: DISTANCE (yds) 200 – 300 – 500 – 600 – 900 – 1000 RISE (mins) 2. 5 6. 5 4. 0 16. 0 7. 0 Note that as you aim further away a greater change in angle is needed to achieve the same effect on the impact point.
Standard Elevation Table for 7. 62 mm
The Elevation Vernier
Elevation Vernier Settings 40 40 20 5 0 0 0 40 5 20 0 0 1 5 20 0 0 4
The Elevation Vernier Set at 6 minutes of elevation
The Elevation Vernier Set at 9 minutes of elevation
The Elevation Vernier Set at 13 minutes of elevation
The Elevation Vernier Set at 31 minutes of elevation
The Wind Vernier
The Effects Of Wind On The Bullet Target Still Air FP FP
Range Flags/Wind Speeds Light 2 mph Gentle 4 mph Moderate 8 mph Fresh 12 mph Strong 16 mph Very Strong 20 mph
The Wind Scale
The Wind Scale 20 0 20 5 0 0 2 LEFT 20 5 20 20 0 5 0 3 RIGHT 5
The Wind Scale Set at 8 min left
Sight Systems Different target shooting disciplines may involve different types of sights eg. • Telescopic sights (F and Match class) • Leaf sights (Older military rifles) • Buckhorn sights (Gallery rifles)
“Service” Rifle Sights Note the different method of sight adjustment
Telescopic Sights Telescopic sight adjustment may be in the opposite direction to that of target sights
Leupold Sight Telescopic sight adjustment may be in the opposite direction to that of target sights
Tasco Sight
NRA Probationary Course Compiled by Dave Burton
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