The M2 rifling features

• A. Right-hand twist, one turn in fifteen inches
• B. Left-hand twist, one turn in fifteen inches
• C. Five lands and grooves
• D. Right-hand twist, one turn in thirty inches

Answer: (A)

The main idea here is how rifling twist stabilizes the bullet. The M2 barrel uses a right-hand twist with one turn in fifteen inches (1:15). This means the bullet spins clockwise as it travels, which provides the right amount of stabilization for the long, heavy .50 BMG projectile at typical combat ranges. A left-hand twist would rotate the bullet the wrong way and wouldn’t match the M2’s design, while a twist of 1:30 would spin the bullet too slowly to stabilize it reliably at distance. Note that the M2 does have five lands and grooves in its rifling, but the most defining feature asked about in this item is the right-hand twist with a 1:15 rate.