[slink182]

Others here have provided component upgrades and techniques to improving your accuracy, so I'm not going to even address that. What I will address is the PHYSICS of BB ballistics - it's the ballistic profile that is being directly affected by the components. In addition, the ballistic profile will be affected by elemental forces.

BBs in flight have a number of components acting on them:

- gravity
- oncoming air friction
- muzzle energy, in fps for the BB weight, as driving by your spring/piston/seal/barrel combination
- BB weight
- atmospheric/weather conditions

Gravity is counteracted by your hop-up, which gives the BB a backspin, which creates a low-pressure zone above it, forcing the BB to lift (Bernoulli's principle).

Air friction creates resistance to flight. A side effect is, at excessively high velocities, BBs create a small low-pressure vacuum/wake immediately behind themselves which can cause instability in flight. This disrupts the lift, as airflow moving around the BB is not smoothly flowing back together. Another affect is that this instability makes the BB MORE susceptible to crosswind flows.

Your spring/piston/seal/barrel combination drives your fps. Other's are providing information on this, so I won't.

BB weight provide stability in flight simply because it is heavier (more initial kinetic energy). A heavier round is less likely to be affected by crosswinds, wake turbulence and light foliage, and it is being kept in the air because of Bernoulli's. A heavier round will also fly truer and farther than a lighter round, assuming all other factors being equal. This is why almost all snipers use a 0.36+ gram round.

Atmospheric/weather conditions can have an effect on flight. BB's tend to behave with more uncertainty under humid and wet conditions. This should be obvious - you have moisture on everything, including the air you're shooting through. The moisture will play havoc with your BB's flight path - the air is "thicker" so more friction and interference is expected. Humid conditions may also cause light condensation inside your rifle barrel after a shot because of the sudden drop from high to low pressure in the barrel, although this is a very minor condition compared to everything else.

Stalker (and others) are correct - a slower, heavier round, properly spun, can easily achieve the ranges of a high fps rifle, but without the flight instabilities inherent to a high fps round.