## What is the formula for ballistic coefficient?

C is the ballistic coefficient for the chosen drag function. The Mach number (M) can be calculated as a ratio between the velocity of the projectile over the speed of sound at standard conditions given by the equation: M= V/S where V is the velocity of the projectile and S is the speed of sound at standard conditions.

**What is the ballistic coefficient of M855?**

0.151

The US Army’s Ballistic Research Laboratory measured a ballistic coefficient (G7 BC) of 0.151 and form factor (G7 i) of 1.172 for the SS109/M855 ball projectile.

**Should I use G1 or G7 ballistic coefficient?**

The simple answer to that is the G1 value normally works better for shorter flat-based bullets, while the G7 value should work better for longer, boat-tailed bullets.

### What is G7 ballistic coefficient?

G7 is an updated equation and the better system of measuring a ballistic coefficient. It provides more accurate and reliable results when calculating trajectory using a ballistics program that allows for a G7 to be used.

**What is the difference between M193 and M855?**

M193 vs M855 The M193 cartridge is a 55 gr lead core surrounded by a copper jacket (FMJ-BT, full metal jacket with boat tail). While the M855 “green tip” cartridge is 62 gr and has a steel core “penetrator” at the tip which helps it go through barriers more easily (also FMJ-BT).

**What is G1 BC and G7 BC?**

G1 and G7 are different models of drag functions that measure ballistic coefficient. Ballistic Coefficient or B.C. is a measurement (or prediction in a lot of cases) of how fast a bullet slows down in a given distance with a given velocity.

#### What’s the difference between G1 BC and G7 BC?

G1 – also known as Ingalls, G1 projectiles are flatbase bullets with 2 caliber nose ogive and are the most common type of bullet. G7 – Bullets with the G7 BC are long 7.5 degree boat-tails, with 10 caliber tangent ogive, and are very popular with manufacturers for extremely low-drag bullets.

**What is the ballistic coefficient of 308?**

308 Winchester bullet has a BC of around . 248, whereas more streamlined and heavier 190-grain spire point boat tail . 308 bullets often have a BC exceeding .