## 1. Configs Values

Reference CfgAmmo Reference for examples of bullets with correct configs. It is probably best to modify an example that’s close to the bullet you are trying to add.

##### All values are in METRIC units!

### 1.1 `CfgWeapons`

Example: M4

```
class CfgWeapons {
class yourWeaponClass {
// >1:7 inch rifle twist
// 7 inches * 25.4(mm/in) = 177.8 mm
// Same as the Capital T in [Miller twist rule](https://en.wikipedia.org/wiki/Miller_twist_rule){:target="_blank"} (convert to metric)
ACE_barrelTwist = 177.8;
// >14.5 in (370 mm)
ACE_barrelLength = 368.3;
// Right handed is 1, Left is -1, none is 0
// Leaving blank will default to 1 (almost everything is right-handed)
// A smooth-bore gun (e.g. shotgun) would be `0`.
ACE_twistDirection = 1;
};
};
```

### 1.2 `CfgAmmo`

Example: `B_556x45_Ball`

```
class CfgAmmo {
class yourAmmoClass {
// Bullet diameter in mm (diameter is a little different from caliber)
ACE_caliber = 5.69;
ACE_bulletLength = 23.012; // Bullet Length in mm
ACE_bulletMass = 4.0176; // Mass in grams (example is roughly 62 grains)
// Standard deviation of the muzzle velocity variation in percent
// Example: With a muzzle velocity of 850 m/s and a standard deviation of 0.35%, 68% of the shots will be between 847 m/s and 853 m/s
ACE_muzzleVelocityVariationSD = 0.35;
// Array of muzzle velocity shifts in m/s with 11 data points from -15 °C to 35 °C
// Example: At 0°C the shift will be -21.0
ACE_ammoTempMuzzleVelocityShifts[] = {-27.20, -26.44, -23.76, -21.00, -17.54, -13.10, -7.95, -1.62, 6.24, 15.48, 27.75};
// Array of ballistic coefficients (contains one element more than the velocity boundary array)
ACE_ballisticCoefficients[] = {0.151};
ACE_velocityBoundaries[] = {}; // Array of velocity boundaries
ACE_standardAtmosphere = "ASM"; // "ASM" or "ICAO"
ACE_dragModel = 7; // Number that specifies the drag model [1, 2, 5, 6, 7, 8]
// Array of muzzle velocities (same size as barrel length array)
ACE_muzzleVelocities[] = {723, 764, 796, 825, 843, 866, 878, 892, 906, 915, 922, 900};
// Array of barrel lengths (same size as muzzle velocity array)
// Example, when shooting with the M4 barrel (`368.3`mm).
// The length is between the 5th and 6th barrelLengths (`360.68, 391.16`).
// So the muzzle velocity will be between 5th and 6th muzzleVelocities (`866, 878`).
ACE_barrelLengths[] = {210.82, 238.76, 269.24, 299.72, 330.2, 360.68, 391.16, 419.1, 449.58, 480.06, 508.0, 609.6};
};
};
```