Sniper Reference
Mil-relation range, BLIR / loophole offset, ballistic coefficients, and field conversions.
Mil-Relation Calculator
Range = (Target Size" x 25.4) / Mil Size
Range (m) = (Target Size (m) x 1000) / Mil Size
Target Size" = (Range x Mil Size) / 25.4
Mil Size = (Target Size" x 25.4) / Range
BLIR Calculator (Loophole)
BLIR = (HOB x 70) / Feet From Loophole
BLIR Rules of Thumb
| 5ft or less | Add 5 mils |
| 10ft | Add 4 mils |
| 15ft | Add 3 mils |
| 20ft or more | Add 2 mils |
1 mil every 10ft = 0.12 inches | .308 bullet is 0.15" from center wide
Loopholes > HO: put target on top and shoot
Ballistic Coefficients (G1)
| Cartridge | G1 BC |
|---|---|
| MK262 (.223) | .362 |
| M118LR (.308) | .475 |
| A191 (.300WM) | .533 |
| MK211 (.50) | .701 |
G1 to G7 conversion: G1 x 0.512
Average Muzzle Velocities
| Platform | MV (fps) |
|---|---|
| M24 | 2650 |
| M2010 | 2950 |
| M110 | 2550 |
High Angle Shooting
| Angle | Hold Adjustment |
|---|---|
| 30 degrees | Shoot 85% of actual hold |
| 45 degrees | Shoot 66% of actual hold |
| 60 degrees | Shoot 50% of actual hold - 0.08 mils |
Wind Analysis
| Speed (mph) | Indicator |
|---|---|
| 0-3 | Hardly felt on face |
| 3-5 | Felt lightly on face |
| 5-8 | Tree leaves in constant motion |
| 8-12 | Raises dust and loose paper |
| 12-15 | Small trees begin to sway |
| 15-20 | Large trees begin to sway, wind becomes audible |
Deflection (MOA) = Range (100s) x Wind Velocity (mph) / 10
Measurements & Conversions
Mil/MOA
| 1 Mil | 3.438 TMOA |
| 1 Mil | 3.5 SMOA |
| 1 Mil | 3.936" |
| 1 Mil (field) | 4" (deviation: 0.64" @ 1000m) |
| 1 TMOA | 0.29 mils |
| 1 SMOA | 0.3 mils |
| 1 TMOA @ 100m | 1.145" |
| 1 SMOA @ 100m | 1" |
| 1 TMOA @ 100yd | 1.047" |
Distance
| 1 inch | 2.54 cm |
| 1 cm | 0.3937 in |
| 1 foot | 0.3048 m |
| 1 meter | 1.0936 yd |
| 1 yard | 0.9144 m |
| 1 meter | 3.2808 ft |
| 1 mile | 1.6093 km |
| 1 km | 0.6213 mile |
Truing Process
| Step | Action |
|---|---|
| 1st True | Speed of sound x 1.2 (Update MV) |
| 2nd True | (Mach 1.0 - Mach 1.2) x 0.75 + Mach 1.2 (find range limit before C1 changes) |
| 3rd True | Beginning of subsonic + 200m (update using C1) |
Miscellaneous Reference
| Cant Effect | Every 2.5 deg of cant = 0.05 mil in direction of cant every 100m |
| Max Ord | Range to target x 0.55 |
| Supersonic | Faster than speed of sound, ends at Mach 1.0 |
| Transonic | Mach 1.2 - 0.8 (transitional stage) |
| Subsonic | Starts at Mach 1.0 |
| Speed of Sound (Mach 1.0) | 1061 + temp of day (fps) |
| FTB | 350 mps |
| Altitude Effect | Every 1000ft gained = 1" inHg |
| Sea Level BP | 29.9" inHg |
RET (Rapid Engagement Technique)
1. After truing weapon system, find actual holds for ranges: 380m, 440m, 510m, 610m
2. Add actual holds to milsize for given range to find RET number
3. Average the 4 RET numbers = your RET number
| Range (m) | Milsize (12") |
|---|---|
| 380 | 0.8 |
| 440 | 0.7 |
| 510 | 0.6 |
| 610 | 0.5 |
.308: Usually a 10 gun at 12" drill
.300WM: Usually a 9 gun at 12" drill
12": Measured from top of head to curvature of shoulders
For 20": Take mil size, cut in half, subtract 9 (for 10 gun) or 8 (for 9 gun)
Wind Bracket 1: RET hold (decimal) + 0.2
Report Formats
GOSS (Ground Objective Surveillance)
SO#/TRGTNAME/DTG/GRID/GOSS#OF#
Breach point | LCC | Routes LU->VDO/Staging area->LCC/LCC->Breach
Obstacles (ground and air) | SO Location (day and night)
North seeking arrow | Sector of fire | # buildings starting w/ target moving clockwise
GSS (Ground Structure Surveillance)
SO#/TRGTNAME/DTG/GRID/DIRECTION/DIST/BUILDINGSIDE/GSS#OF#
North seeking arrow | Building dimensions (ft) | Breach Points
Opening # System | Obstacles | Roof Identification
ANGUS (Activity Notification)
SO element + OBJ Name | SO location (8 dig MGRS)
Casualties/Disposition of Team | Location of MSS/PB (8 dig MGRS)
DTG Surveillance established | Additional Info
BORIS (Biometric/Observation Report)
SO#/TRGTNAME/DTG/BORIS#OF#
Size | Activity | Location | Unit | Time
Equipment | Sex | Nationality | Age | Physical Description
SNAP (Short Notification of Activity/Persons)
SO#/TRGTNAME/DTG/SNAP#OF#
Sex | Nationality | Age | Physical Description