257 Weatherby Magnum Ballistics

257 Weatherby Magnum:

The 257 Weatherby Magnum was introduced to the public in the mid 1940’s by Roy Weatherby as one of his original cartridges and his personal favorite as well. The 257 Weatherby Magnum cartridge case itself is the 300 H&H; magnum case necked down to 25 caliber and blown out the full length of the case which then sports a double radius shoulder and shortened to 2.545″ with a long neck.

The 257 Weatherby Magnum is a extremely flat shooting dual purpose cartridge and is the fastest of all commercially available 25 caliber cartridges, sending a 80 grain bullet out the muzzle at 3,870 feet per second for varmints and able to send a 115 grain bullet out the muzzle at 3,400 feet per second for deer sized game.

The 257 Weatherby Magnum with the power it offers down range will also recoil somewhat to the shooters shoulder but is still manageable to shoot. The 257 Weatherby Magnum definitely needs a 26″ barrel length for a more complete powder burn as the muzzle blast and flash are fairly high for any barrel length shorter.

To achieve maximum accuracy from your 257 Weatherby Magnum rifle there are several things you need to do correctly that will help increase your rifles overall accuracy capabilities.

First: Properly mount your riflescope.
Second: Properly break-in your rifle barrel.
Third: Properly sight-in your rifle.

.257 Weatherby Magnum Ballistics:

87 Grain Bullet Down Range	At 100 Yards	At 200 Yards	At 300 Yards	At 400 Yards	At 500 Yards
These are down range trajectory charts for the 257 Weatherby Magnum cartridge with the scope mounted 1.8 inches above the bore center line plus if you were using these loads, their effective hunting bullet energy range with well placed shots on; Predators: Such As, Bobcat, Cougar And Coyote. Deer Size Game: Such As, Antelope, Blacktail Deer, Hogs, Javelina, Mule Deer And Whitetail Deer.
Good Predator Hunting Load: 257 Wby. Mag. rifle cartridge manufacturer: Weatherby. Bullet weight: 87 Grains. Bullet ballistic coefficient: .322. Bullet muzzle velocity: 3,825 Feet Per Second. Bullet muzzle energy: 2,826 Foot Pounds. Bullet trajectory is set at 1 inch mid-range rise. Rifle true zero is 217 Yards. Maximum point blank range is 248 yards.
Trajectory in Inches:	+ 0.8	+ 0.4	– 3.5	– 11.6	– 25.1
Energy in Foot Pounds:	2,328	1,913	1,565	1,271	1,022
Predator Effectiveness:	+	+	+	+	+
Good Deer Hunting Load: 257 Wby. Mag. rifle cartridge manufacturer: Weatherby. Bullet weight: 115 Grains. Bullet ballistic coefficient: .453. Bullet muzzle velocity: 3,400 Feet Per Second. Bullet muzzle energy: 2,952 Foot Pounds. Bullet trajectory is set at 2 inch mid-range rise. Rifle true zero is 247 Yards. Maximum point blank range is 285 yards.
115 Grain Bullet Down Range	At 100 Yards	At 200 Yards	At 300 Yards	At 400 Yards	At 500 Yards
Trajectory in Inches:	+ 1.5	+ 1.4	– 2.7	– 11.4	– 25.6
Energy in Foot Pounds:	2,566	2,227	1,926	1,659	1,422
Deer Effectiveness	+	+	+	+	+

257 Wby. Mag. Rifle Cartridge Manufacturer	Bullet Weight Grains	Bullet Ballistic Coefficient	Muzzle Velocity Fps.	Muzzle Energy Ft. lbs.	Recoil Energy Ft. lbs.
Rifle: Barrel Length – 26″. Bore Twist Rate Early – 1 in 12″ / Current – 1 in 10″. Bore Groove Diameter – .257″.
Cartridge: Bullet Diameter – .257″. Primer Size – Large Rifle. Primer Type – Magnum. Case Neck Diameter – .283″. Case Shoulder Diameter – .492″. Case Base Diameter – .512″. Case Rim Diameter – .531″. Trimmed Case Length – 2.540″. Maximum Case Length – 2.550″. Maximum Overall Length – 3.250″.
Weatherby	80	.378	3,870	2,660	14.79
Weatherby	87	.322	3,825	2,826	15.90
Weatherby	100	.357	3,602	2,881	17.14
Weatherby	110	.418	3,460	2,924	18.05
Weatherby	115	.453	3,400	2,952	18.47
Weatherby	117	.243	3,402	3,007	18.71
Weatherby	120	.391	3,305	2,910	18.50