Direct answer first: The performance of a projectile fired from a firearm is governed by a combination of internal, external, and terminal factors. Key influences include the cartridge and gunpowder (propellant energy and burn characteristics), bullet design (weight, shape, material, and ballistic coefficient), barrel characteristics (twist rate, length, and rifling), and atmospheric conditions (air density, temperature, wind). All of these interact to determine muzzle velocity, stability, drift, drag, and impact behavior.

Core factors

• Propellant and load
  • Type and amount of powder determine pressure, muzzle velocity, and chamber pressure. Different powders burn at different rates, affecting peak pressure and the acceleration of the bullet inside the barrel. This in turn influences bullet stabilization, velocity consistency, and potential pressure-related effects. [related ballistic sources discuss internal ballistics and how propellant charge shapes performance]

• Bullet design and mass
  • Bullet weight (mass) and geometry (ogive shape, point profile, boat-tail, hollow point) affect aerodynamic drag and stability. Higher ballistic coefficient (BC) generally means reduced drag and better retained velocity downrange, improving stability and range. Material composition and density also influence gyroscopic stability and expansion characteristics on impact.

• Barrel and firearm characteristics
  • Barrel length and twist rate determine how quickly the bullet spins up to stable gyroscopic motion. If the twist is too slow for a heavy bullet, stability can be poor; if too fast for a light bullet, it can also cause instability. Barrel harmonics and wear can modulate muzzle velocity and point of impact.

• Environmental conditions
  • Air density (affected by temperature, pressure, humidity, and altitude) governs drag on the bullet during flight. Higher density air slows the bullet more than low-density air; wind (speed and direction) induces lateral and vertical deflection. Atmospheric changes can shift drop and drift noticeably over long ranges.

• External ballistics phenomena
  • Drag, lift, and stability influence the trajectory. Spin drift, Coriolis and Eötvös effects may become relevant at long ranges and high speeds, particularly for long-range shooting. These factors require precise ballistic calculations and corrections.

• Terminal performance
  • On impact, the interaction with a target depends on bullet construction (expansion, fragmentation, penetration) and target properties, which determine energy transfer and penetration depth.

Quick practical implications

• For accuracy at distance, match bullet weight and design to the rifle’s bore and twist rate, and select a propellant load that yields consistent muzzle velocity within the rifle’s operating pressure range.

• To optimize downrange performance, consider bullets with high ballistic coefficient suited to the expected range and wind conditions, while accounting for environmental variables.

• Always verify compatibility between bullet type and barrel (especially when using non-traditional bullet materials), as mismatches can affect stability and accuracy.

If you’d like, narrow this down to a specific firearm, cartridge, or range scenario and include target distance and expected environmental conditions, and a more tailored breakdown with concrete variables and example calculations can be provided.