Understanding How a Bullet Flies
Earlier than we get into the specifics of the .308 and the 168-grain bullet, let’s lay a basis by discussing the basic rules that govern a bullet’s path via the air. The examine of a bullet’s flight is named ballistics, broadly categorized into a number of phases.
Inside Ballistics
This encompasses what occurs *inside* the firearm from the second the set off is pulled to the second the bullet exits the muzzle. It is concerning the ignition of the primer, the speedy enlargement of propellant gases, and the acceleration of the bullet down the barrel.
Exterior Ballistics
That is the stage we’re most involved with. Exterior ballistics examines the bullet’s trajectory after it leaves the muzzle, specializing in elements that affect its path. These embody gravity, air resistance, wind, and the bullet’s ballistic coefficient.
Terminal Ballistics
This section offers with what occurs when the bullet *hits* the goal. It is concerning the bullet’s impression, the switch of vitality, and the ensuing results on the goal, be it a sport animal or a paper goal.
A number of key phrases are elementary to comprehending exterior ballistics:
Muzzle Velocity
That is the velocity at which the bullet leaves the barrel, measured in toes per second (fps) or meters per second (m/s). It’s a main consider figuring out the bullet’s trajectory and vary.
Ballistic Coefficient
This numerical worth quantifies a bullet’s capacity to beat air resistance. A better ballistic coefficient (BC) means the bullet is extra aerodynamic and resists air drag extra successfully. This usually interprets to much less drop and fewer wind drift over lengthy distances.
Bullet Drop
Gravity relentlessly pulls on all objects, together with bullets. Bullet drop refers back to the vertical distance a bullet falls over a given distance. This drop necessitates aiming barely above the goal to compensate.
Wind Drift
Wind is one other main issue. It pushes the bullet sideways, inflicting it to float off target. The quantity of wind drift relies on the wind velocity, the angle of the wind, and the bullet’s BC.
Power
As a bullet travels, it possesses kinetic vitality, which is a measure of its capacity to do work. Power is usually measured in foot-pounds (ft-lbs) or Joules. The vitality of a bullet is highest on the muzzle and reduces because the bullet slows down.
The .308 with the 168-Grain Benefit
Why is the 168-grain bullet so standard within the .308 Winchester? The reply lies in its versatility and balanced efficiency traits. It sits in a candy spot the place some great benefits of energy, accuracy, and manageable recoil come collectively.
Accuracy
The 168-grain bullet is usually favored by goal shooters due to its inherent accuracy. Many rifles are designed, and barrels are rifled, to optimize their efficiency with bullets of this weight.
Efficient Vary
Whereas the .308 Winchester may be efficient at longer ranges, the 168-grain bullet gives an optimum mix of trajectory and retained vitality for a lot of searching and goal capturing situations. It carries sufficient vitality to ship moral kills on medium-sized sport whereas additionally sustaining acceptable downrange ballistics for aggressive capturing at numerous distances.
Recoil
In comparison with heavier bullets, the 168-grain bullet produces much less recoil, making it extra snug to shoot. Lowered recoil permits for faster follow-up photographs and usually improves capturing accuracy.
Past the overall advantages, it’s essential to acknowledge that the precise traits of a 168-grain bullet will range based mostly on the producer, bullet design, and the propellant load. The ballistic coefficient, muzzle velocity, and downrange efficiency might be barely completely different for every load. Subsequently, you have to seek the advice of load information for the *particular* ammunition you’re utilizing.
Placing it on Paper: The Ballistics Chart
To successfully make the most of a .308 rifle with a 168-grain bullet, you have to perceive its trajectory. Essentially the most great tool for it is a ballistics chart. This offers a concise, but correct illustration of how a bullet travels. As a result of each rifle and cargo will carry out barely in a different way, this chart is a generalized guideline. Nevertheless, it offers a place to begin for studying and may be adjusted as you experiment and refine your understanding.
*Necessary Be aware: The next chart offers information that’s consultant for a preferred 168-grain bullet, however the information will range with every particular person firearm, ammunition, and atmospheric situations.*
The numbers under assume a bullet with a Ballistic Coefficient (BC) of .462, and a muzzle velocity of 2700 fps. Different elements are a zero at 100 yards, and normal sea degree situations (59°F / 15°C, 29.92 inHg atmospheric strain). This information is for illustrative functions solely. ALWAYS seek the advice of the producer of your chosen ammunition, or a certified ballistics calculator, for particular load information.
| Vary (Yards) | Drop (Inches) | Wind Drift (inches, 10 mph Crosswind) | Velocity (fps) | Power (ft-lbs) |
|---|---|---|---|---|
| 0 | 0.0 | 0.0 | 2700 | 2711 |
| 50 | -0.7 | 0.8 | 2545 | 2429 |
| 100 | 0.0 | 3.4 | 2398 | 2149 |
| 150 | -2.9 | 7.9 | 2258 | 1897 |
| 200 | -8.3 | 14.3 | 2127 | 1686 |
| 250 | -17.5 | 22.8 | 2002 | 1495 |
| 300 | -30.8 | 33.5 | 1885 | 1319 |
| 400 | -70.7 | 62.9 | 1667 | 1038 |
| 500 | -132.7 | 102.6 | 1473 | 811 |
Utilizing the Chart: A Sensible Information
Let’s have a look at the way to use this chart. If you’re capturing at 300 yards, you’ll anticipate your bullet to drop roughly 30.8 inches under your level of goal. Moreover, if there’s a crosswind of 10 mph, you’ll see roughly 33.5 inches of drift.
From Principle to Follow: Zeroing at 100 Yards
A *zero* is the method of adjusting your rifle’s sights (scope or iron sights) in order that the bullet impacts the goal at a particular vary, often the vary at which you intend on utilizing the rifle. Zeroing at 100 yards is a sensible place to begin for the .308 with a 168-grain bullet. This provides you a very good stability of accuracy and permits for simple adjustment for longer-range photographs.
This is the way to obtain a 100-yard zero:
Collect Your Gear
You’ll want your rifle, your scope (if relevant), ammunition (the 168-grain .308 load you plan to make use of), a secure capturing platform (a bench, capturing bag, or tripod), a goal (ideally with grid strains), and a method to measure distances precisely (a rangefinder is greatest, however a tape measure will work if wanted).
Guarantee Secure Practices
All the time, *all the time*, observe protected gun-handling guidelines. Confirm the firearm is unloaded and pointed in a protected route. Put on eye and ear safety. Solely load the rifle while you’re able to shoot, and all the time deal with each firearm as if it’s loaded.
Put together Your Rifle
Earlier than even firing a shot, get your scope in your rifle. In case you have a brand new scope, you’ll have to mount it and get it as sq. with the receiver as potential.
Bore Sighting
Earlier than you begin capturing, use bore sighting. This may be accomplished by eradicating the bolt from the rifle and searching via the bore (the barrel) to see the goal. This helps you align the bore with the goal.
Preliminary Photographs and Changes
Now, arrange your goal at 100 yards. Take a couple of fastidiously aimed photographs. The primary few photographs will seemingly be off beam. Take a look at the goal and observe the place your photographs are hitting relative to your level of goal. Use your scope’s changes (turrets) to maneuver your level of impression to the middle of the goal.
Most scopes have markings on their turrets that point out the quantity of adjustment per click on. (e.g., ¼ MOA (minute of angle) or 1/8 MOA). A ¼ MOA adjustment will transfer your bullet impression roughly ¼ inch at 100 yards. Make the required changes to your scope to maneuver your level of impression to the middle of the goal. In case your photographs are excessive and left, you’ll modify your scope down and proper, and vice versa.
High-quality-Tuning
After making changes, hearth one other group of photographs. Consider the place your photographs are impacting. Make additional, extra exact changes till your group of photographs facilities in your level of goal.
Understanding the Different Variables
Whereas a 100-yard zero is a superb basis, a number of elements will affect your bullet’s trajectory past that vary.
Wind
Wind is a big affect on bullet flight. The stronger the wind, and the longer the gap to the goal, the extra the wind will have an effect on your bullet’s path. Studying wind requires observe, expertise, and an understanding of how wind impacts your chosen load. Studying to estimate wind velocity, wind route, and making use of these estimations to your photographs is essential for long-range accuracy. The chart offered above provides you some concept of the wind drift, however it will change based mostly on the precise wind velocity.
Altitude and Air Density
Altitude additionally impacts ballistics. At increased altitudes, the air is much less dense, which reduces air resistance and can lead to a flatter trajectory and fewer wind drift. Temperature additionally performs a component in air density, and thus, ballistics. You may compensate for these variables via using ballistics calculators, which let you enter environmental situations.
Different Environmental Results
Humidity can affect the ballistics, however its impact is often minimal until you’re capturing at excessive distances or in very humid situations.
Extending the Vary
Utilizing your 100-yard zero and a ballistics chart, you may lengthen the efficient vary of your rifle. You need to use the chart to find out how a lot to “maintain over” or goal above your goal, at completely different distances, to compensate for bullet drop. Some shooters additionally use scope reticle markings (like mil-dots or MOA hash marks) to assist in holdover. A rangefinder and a very good understanding of windage changes turn out to be indispensable at longer distances.
Selecting the Proper Load
The 168-grain bullet is a flexible alternative, however you will see that it in numerous configurations.
Match Bullets
These are designed for max accuracy and are usually utilized in goal capturing.
Looking Bullets
These are designed to broaden on impression, creating a bigger wound channel and maximizing terminal efficiency.
Choosing the proper bullet relies on the appliance. In case your main focus is goal capturing, a match bullet will most likely serve your wants greatest. For those who’re planning on searching, choose a searching bullet designed for the sport you’re pursuing. All the time do your homework and select the fitting device for the job.
Wrapping Up
Understanding the basics of ballistics is vital to success with any firearm. The .308 Winchester, loaded with a 168-grain bullet, gives an awesome mix of energy and accuracy. A 100-yard zero offers an efficient basis. By understanding the ballistics, utilizing a ballistics chart, and practising constantly, you’ll be properly in your method to reaching constant hits in your targets, at ranges out to a number of hundred yards and even past.
All the time keep in mind that accountable firearm possession requires a dedication to security and ongoing training. Continued observe and the willingness to be taught are important for any marksman.
