1-a-www-gunnersden-com.gif - 1757 Bytes 1-b-rifles-logo.gif - 1903 Bytes 1-c-guide.gif - 780 Bytes
1-d-home.gif - 1035 Bytes Muzzleloader Ballistics - Centerfire Rifle Ballistics - Rimfire Rifle Ballistics.
Rifle Scope Sight-In - Hunting Rifle Sight-In - Rifle Shooting - Rifling Twist Rates - Rifling Twist Effects.
1-e.gif - 1496 Bytes
1-f.gif - 535 Bytes

 Bolt Action Rifles
 Autoloading Rifles
 Barrel Twist Rates
 Barrel Break-In
 Rifle Scopes
 Rifle Scope Mounts
 Rifle Scope Mounting
 Rifle Scope Sight-In
 Hunting Rifle Sight-In
 Precision Targets
 Rifle Shooting
 Precision Bold Targets.
 Rimfire Ballistics
 Centerfire Ballistics
 Reloading
 Equipment
 How To
 Black Powder
 Recoil
 Reloading Accuracy
 Brass
 Primers
 Powder
 Bullets
 Load Testing
 Run-Out
1-i-information.gif - 1870 Bytes

270 Winchester / Hunting & Ballistics:
Written by: Kim Lockhart, Copyright.

External Ballistics:
 External ballistics pertains to bullet velocity, energy and trajectory down-range. Bullet trajectory is the flight path of the bullet relative to some known and fixed points.

Bullet Trajectory And Sighting Plane:
 1. Point blank range when sighting in a rifle is the first point at which the line of sight intersects with the bullets path in the bullets trajectory.
 2. Mid-range rise when sighting in a rifle is the highest point in the bullets trajectory between the point blank range and true zero.
 3. True zero when sighting in a rifle is the second point at which the line of sight intersects with the bullets path in the bullets trajectory.
 4. Maximum point blank range when sighting in a rifle is the height of the mid-range rise and the bullet drop beyond true zero, both are equal in measure.

correct-trajectory-sight-plane
correct-trajectory-sight-plane-scope-view

Rifle Sight Height And Bullet Trajectory:
 To properly sight-in a hunting rifle a person needs to know a little bit about their scope mount height of their rifle as this affects the sight plane that intersects with the bullet's trajectory.
Rifle Sight Height to Bore Center Line:
Open Sights = 1 inch sight height.
Rifle Scope Center Line to Bore Center Line:
Standard 1 Inch Diameter Scope Tube.
Low Scope Mount And Rings = 1.5 inch sight height.
Medium Scope Mount And Rings = 1.8 inch sight height.
High Scope Mount And Rings = 2.0 inch sight height.

Rifle Barrel Length, Bullet Velocity And Energy:
 Bullet velocity readings are generally taken from a rifle barrel length of 24 inches and using the following formula the bullets energy is determined; velocity x velocity x bullet weight = _ divided by 450,340 = bullet kinetic energy in foot pounds. If your rifle barrel length is not 24 inches then you have to recalculate the bullet velocity and bullet energy, bullet velocity deviation by barrel length;
Rifle Barrel Length Shorter Than 24 Inch You Subtract Velocity.
Rifle Barrel Length Longer Than 24 Inch You Add Velocity.
2,500 to 3,000 feet per second advertised velocity, adjust at 20 feet per second per inch from standard of 24 inch rifle barrel.
3,000 to 3,500 feet per second advertised velocity, adjust at 30 feet per second per inch from standard of 24 inch rifle barrel.
3,500 to 4,000 feet per second advertised velocity, adjust at 40 feet per second per inch from standard of 24 inch rifle barrel.

Bullet Ballistic Coefficient:
 The bullet ballistic coefficient, higher B.C.s mean flatter trajectories and higher retained energy down-range on target. A ballistic coefficient is the measure of a bullet's relative ability to overcome air resistance. Each bullet is assigned a numerical value expressing this efficiency. Ballistic coefficient calculations combine both shape and sectional density factors.

Bullet Energy:
 Before the bullet is down-range and on target, you have to know whether the bullet will have enough energy retention to cleanly harvest the animal. A bullet's kinetic energy is measured in foot pounds, and this is a proxy for what's generally termed stopping-power. The higher a bullet's energy at the point of impact, the greater its stopping-power.

Target Size And Bullet Energy Needs:
 Just as important is the size of target that a game animal that your hunting presents to you, typically standing broadside, exposing heart and lung area. Below are several hunting ballistics and sight-in charts for 270 Winchester ammunition that categorize this ammunition to its practical use on various game animals for hunting at various distances.


270 Winchester And Moose Size Game Hunting:
Moose Size Animals Include: Grizzly Bear, Brown Bear And Moose. These animals are quite large and offer about an eight inch target zone, for a correct rifle sight-in, a four inch mid-range is required for minimum bullet trajectory effect.
For this size animal, I prefer 2,000 foot pounds of bullet energy.
270 Winchester Hunting Ammunition:
Ammuntion: Winchester 270 Win. XP3 150 Grain.
Bullet Diameter: .277 Inch.
Bullet Weight: 150 Grains.
Bullet Ballistic Coeffecient: .503.
Rifle Barrel Length: 24 Inches.
Rifle scope is mounted 1.8 inches above bore center-line.
Rifle bullet trajectory set at 4 inch mid-range rise.
Rifle true zero is 282 Yards.
Maximum point blank range is 335 yards.
Note: (FPS. = Feet Per Second.) (IN. = Inches.) (FT. LBS. = Foot Pounds.)
Range
Muzzle
100 yds.
200 yds.
300 yds.
400 yds.
500 yds.
Bullet Velocity / FPS.:
2,950
2,763
2,584
2,412
2,247
2,088
Bullet Trajectory / IN.:
- 1.8"
+ 3.2"
+ 3.5"
- 1.3"
- 12.1"
- 29.8"
Bullet Energy / FT. LBS.:
2,898
2,543
2,225
1,938
1,682
1,432
Moose Size Animals:
+
+
+
+
-
-


270 Winchester And Elk Size Game Hunting:
Elk Size Animals Include: Caribou, Black Bear, Sheep And Elk. These animals can be quite large and offer about an six inch target zone, for a correct rifle sight-in, a three inch mid-range is required for minimum bullet trajectory effect.
For this size animal, I prefer 1,800 foot pounds of bullet energy.
270 Winchester Hunting Ammunition:
Ammuntion: Hornady 270 Win. Superformace 140 Grain.
Bullet Diameter: .277 Inch.
Bullet Weight: 140 Grains.
Bullet Ballistic Coeffecient: .495.
Rifle Barrel Length: 24 Inches.
Rifle scope is mounted 1.8 inches above bore center-line.
Rifle bullet trajectory is set at 3 inch mid-range rise.
Rifle true zero is 265 Yards.
Maximum point blank range is 315 yards.
Note: (FPS. = Feet Per Second.) (IN. = Inches.) (FT. LBS. = Foot Pounds.)
Range
Muzzle
100 yds.
200 yds.
300 yds.
400 yds.
500 yds.
Bullet Velocity / FPS.:
3,090
2,894
2,706
2,526
2,353
2,187
Bullet Trajectory / IN.:
- 1.8"
+ 2.4"
+ 2.5"
- 2.2"
- 12.3"
- 28.8"
Bullet Energy / FT. LBS.:
2,968
2,603
2,276
1,983
1,721
1,487
Elk Size Animals:
+
+
+
+
+
-


270 Winchester And Deer Size Game Hunting:
Deer Size Animals Include: Antelope, Blacktail Deer, Hogs, Javelina, Mule Deer And Whitetail Deer. These animals can be somewhat small at times and offer about an four inch target zone, for a correct rifle sight-in, a two inch mid-range is required for minimum bullet trajectory effect.
For this size animal, I prefer 1,200 foot pounds of bullet energy.
270 Winchester Hunting Ammunition:
Ammuntion: Hornady 270 Win. Superformace 130 Grain.
Bullet Diameter: .277 Inch.
Bullet Weight: 130 Grains.
Bullet Ballistic Coeffecient: .460.
Rifle Barrel Length: 24 Inches.
Rifle scope is mounted 1.8 inches above bore center-line.
Rifle bullet trajectory is set at 2 inch mid-range rise.
Rifle true zero is 235 Yards.
Maximum point blank range is 272 yards.
Note: (FPS. = Feet Per Second.) (IN. = Inches.) (FT. LBS. = Foot Pounds.)
Range
Muzzle
100 yds.
200 yds.
300 yds.
400 yds.
500 yds.
Bullet Velocity / FPS.:
3,200
2,984
2,778
2,582
2,393
2,213
Bullet Trajectory / IN.:
- 1.8"
+ 1.7"
+ 1.2"
- 3.8"
- 13.9"
- 30.2"
Bullet Energy / FT. LBS.:
2,955
2,570
2,228
1,924
1,653
1414
Deer Size Animals:
+
+
+
+
+
+

Hunting Ballistics
223 Rem.
243 Win.
25-06 Rem.
6.5 x 55mm
270 Win.
7mm Rem. Mag.
30-30 Win.
308 Win.
30-06 Sprg.
300 Win. Mag.

The Hunter's Guide To Ballistics:
Caldwell Stable Table
Caldwell Lead Sled Plus Recoil Reducing Rifle Rest
Caldwell Ultimate Target Stand With Target Backer

Rifle Scope Sight-In - Hunting Rifle Sight-In - Rifle Shooting - Rifling Twist Rates - Rifling Twist Effects