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 ideas that govern a bullet’s path by the air. The examine of a bullet’s flight is known as ballistics, broadly categorized into a number of phases.
Inner 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 in regards to 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 components that affect its path. These embrace 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 in regards to the bullet’s influence, the switch of power, and the ensuing results on the goal, be it a sport animal or a paper goal.
A number of key phrases are basic to comprehending exterior ballistics:
Muzzle Velocity
That is the velocity at which the bullet leaves the barrel, measured in ft per second (fps) or meters per second (m/s). It’s a major consider figuring out the bullet’s trajectory and vary.
Ballistic Coefficient
This numerical worth quantifies a bullet’s capability 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 track. The quantity of wind drift is determined by the wind velocity, the angle of the wind, and the bullet’s BC.
Vitality
As a bullet travels, it possesses kinetic power, which is a measure of its capability to do work. Vitality is usually measured in foot-pounds (ft-lbs) or Joules. The power 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 widespread within the .308 Winchester? The reply lies in its versatility and balanced efficiency traits. It sits in a candy spot the place the benefits of energy, accuracy, and manageable recoil come collectively.
Accuracy
The 168-grain bullet is commonly 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 could be efficient at longer ranges, the 168-grain bullet gives an optimum mix of trajectory and retained power for a lot of looking and goal capturing situations. It carries sufficient power 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 comfy to shoot. Lowered recoil permits for faster follow-up pictures and usually improves capturing accuracy.
Past the final advantages, it’s essential to acknowledge that the particular traits of a 168-grain bullet will range primarily based on the producer, bullet design, and the propellant load. The ballistic coefficient, muzzle velocity, and downrange efficiency will probably be barely totally different for every load. Due to this fact, you need to seek the advice of load information for the *particular* ammunition you might be utilizing.
Placing it on Paper: The Ballistics Chart
To successfully make the most of a .308 rifle with a 168-grain bullet, you need to perceive its trajectory. Essentially the most useful gizmo for this can be a ballistics chart. This supplies a concise, but correct illustration of how a bullet travels. As a result of each rifle and cargo will carry out barely in another way, this chart is a generalized guideline. Nevertheless, it supplies a place to begin for studying and could be adjusted as you experiment and refine your understanding.
*Essential Word: The next chart supplies information that’s consultant for a well-liked 168-grain bullet, however the information will range with every particular person firearm, ammunition, and atmospheric circumstances.*
The numbers beneath assume a bullet with a Ballistic Coefficient (BC) of .462, and a muzzle velocity of 2700 fps. Different components are a zero at 100 yards, and normal sea stage circumstances (59°F / 15°C, 29.92 inHg atmospheric stress). This information is for illustrative functions solely. ALWAYS seek the advice of the producer of your chosen ammunition, or a professional ballistics calculator, for particular load information.
| Vary (Yards) | Drop (Inches) | Wind Drift (inches, 10 mph Crosswind) | Velocity (fps) | Vitality (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 how one can use this chart. In case you are capturing at 300 yards, you’ll count on your bullet to drop roughly 30.8 inches beneath 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 propose on utilizing the rifle. Zeroing at 100 yards is a sensible start line for the .308 with a 168-grain bullet. This provides you a great stability of accuracy and permits for simple adjustment for longer-range pictures.
This is how one can obtain a 100-yard zero:
Collect Your Gear
You’ll want your rifle, your scope (if relevant), ammunition (the 168-grain .308 load you propose to make use of), a steady capturing platform (a bench, capturing bag, or tripod), a goal (ideally with grid strains), and a approach 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*, comply with secure gun-handling guidelines. Confirm the firearm is unloaded and pointed in a secure course. Put on eye and ear safety. Solely load the rifle whenever 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. When you’ve got 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 carried out by eradicating the bolt from the rifle and looking out by 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 just a few fastidiously aimed pictures. The primary few pictures will probably be off track. Have a look at the goal and word the place your pictures are hitting relative to your level of goal. Use your scope’s changes (turrets) to maneuver your level of influence 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 influence roughly ¼ inch at 100 yards. Make the required changes to your scope to maneuver your level of influence to the middle of the goal. In case your pictures are excessive and left, you’ll alter your scope down and proper, and vice versa.
Effective-Tuning
After making changes, fireplace one other group of pictures. Consider the place your pictures are impacting. Make additional, extra exact changes till your group of pictures facilities in your level of goal.
Understanding the Different Variables
Whereas a 100-yard zero is a good basis, a number of components 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 follow, expertise, and an understanding of how wind impacts your chosen load. Studying to estimate wind velocity, wind course, and making use of these estimations to your pictures is essential for long-range accuracy. The chart supplied above provides you some thought of the wind drift, however this can change primarily based on the precise wind velocity.
Altitude and Air Density
Altitude additionally impacts ballistics. At greater altitudes, the air is much less dense, which reduces air resistance and may end up in a flatter trajectory and fewer wind drift. Temperature additionally performs a component in air density, and thus, ballistics. You possibly can compensate for these variables by using ballistics calculators, which let you enter environmental circumstances.
Different Environmental Results
Humidity can affect the ballistics, however its impact is often minimal until you might be capturing at excessive distances or in very humid circumstances.
Extending the Vary
Utilizing your 100-yard zero and a ballistics chart, you may prolong 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 totally 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 great understanding of windage changes turn out to be indispensable at longer distances.
Selecting the Proper Load
The 168-grain bullet is a flexible selection, however you’ll find 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 influence, creating a bigger wound channel and maximizing terminal efficiency.
Choosing the proper bullet is determined by the appliance. In case your major focus is goal capturing, a match bullet will in all probability serve your wants greatest. For those who’re planning on looking, choose a looking bullet designed for the sport you might be pursuing. All the time do your homework and select the best software 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 a fantastic mix of energy and accuracy. A 100-yard zero supplies an efficient basis. By understanding the ballistics, utilizing a ballistics chart, and practising persistently, you’ll be effectively in your approach to reaching constant hits in your targets, at ranges out to a number of hundred yards and even past.
All the time do not forget that accountable firearm possession requires a dedication to security and ongoing schooling. Continued follow and the willingness to study are important for any marksman.
