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 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
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270 WSM / History:
Centerfire Rifle Cartridges
Written by: Kim Lockhart, Copyright.

270 WSM:
 The 270 WSM is a new centerfire rifle cartridge developed in partnership with Browning Arms Company and Winchester ammunition, making its debut and introduced to the shooting public in 2001. The new .277" short magnum cartridge is chambered in Winchester's Model 70 bolt action rifle. The 270 WSM is a commercial cartridge based on the 404 jeffery cartridge case, shortening to 2.100" and necking down to .277" caliber and sharpening the shoulder angle to 35 degrees the new 270 WSM cartridge has plenty of case capacity. The 270 WSM cartridge achieves its useful purpose as an excellent cartridge for white-tailed deer, mule deer, sheep, elk, moose and bears, .277" caliber is a time proven caliber for deer size animals.

 The 270 Winchester Short Magnum cartridge is a well thought out cartridge as Winchester is no stranger in .277" caliber cartridge development. Winchester has now developed 2 cartridges in this caliber; (270 Winchester in 1923), and (270 Winchester Short Magnum in 2001). The 270 WSM factory loadings show a velocity of 3,275 feet per second for a 130 grain bullet for deer hunting and this translates to moderate recoil for the shooter with plenty of bullet energy at the 500 yard mark to flatten a white-tailed deer size animal. The 140 grain bullet serves the elk hunter well all the way out to 400 yards and the 150 grain bullet will certainly handle moose size animals all the way out to 300 yards. The 270 WSM cartridge, chambered in a short actioned light weight rifle may well be the ultimate combination for a superb mountain rifle in rugged terrain.

270 Winchester Short Magnum Cartridge Dimensions:
Bullet Diameter = .277".
Neck Diameter = .314".
Shoulder Diameter = .538".
Shoulder Angle = 35 Degrees.
Base Diameter = .555".
Rim Diameter = .535".
Case Body Length = 1.664".
Case Shoulder Length = .160".
Case Neck Length = .276".
Case Overall Length = 2.100".
Cartridge Overall Length = 2.860".

270 Winchester Short Magnum Rifle Barrel Specifications:
Bore Groove Diameter = .277".
Barrel Length = 24".
Barrel Twist Rate = 1 in 10".

270 Winchester Short Magnum Rifle Accuracy:
Properly mount your rifle scope.
Properly break-in your rifle barrel.
Properly sight-in your rifle using a accurate sight-in target.

Ballistics

Winchester, 270 WSM Ammunition Short Range Ballistics Chart:
Winchester
Bullet
Type:
Bullet
Weight
Grains
Bullet
Ballistic
Coefficient
Muzzle
Velocity
Fps.
Muzzle
Energy
Ft. Lbs.
Rifle
Zero
100 Yds.
Bullet
Drop
200 Yds.
Bullet
Drop
250 Yds.
Ballistic Silvertip 130 .433 3,275 3,096 0 - 2.3" - 5.0"
E-Tip 130 .459 3,275 3,096 0 - 2.2" - 4.9"
Power Max 130 .340 3,275 3,096 0 - 2.4" - 5.4"
Power Core 130 .360 3,275 3,096 0 - 2.4" - 5.3"
XP3 130 .436 3,275 3,096 0 - 2.3" - 5.0"
Accubond CT 140 .472 3,200 3,184 0 - 2.4" - 5.2"
Power Point 150 .344 3,150 3,304 0 - 2.8" - 6.0"
Ballistic Silvertip 150 .496 3,120 3,242 0 - 2.6" - 5.6"
XP3 150 .503 3,120 3,242 0 - 2.6" - 5.6"

Reloading

270 Winchester Short Magnum Reloading Specifications:
Bullet Diameter = .277".
Maximum Case Length = 2.100".
Trimmed Case Length = 2.090".
Primer Size = Large Rifle.

270 Winchester Short Magnum Accuracy Reloading:
Accuracy, Brass, Primers, Powder, Bullets, Load Testing, Run-Out.

 For the Deer, Elk or Moose hunter hand-loading or reloading his or her own 270 Winchester Short Magnum ammunition, Western Powders, Accurate Magpro rifle powder does an impressive job of launching 140 grain .277" diameter bullets at high velocity. Accurates online reloading data shows that a 140 grain .277" diameter Hornady Boat-Tail bullet using 66.8 grains of Accurate Magpro powder can be driven to a velocity of 2,985 feet per second loaded at a maximum cartridge overall length of 2.760" in the 270 WSM. This load does not top out until the 140 grain bullet is at 3,275 feet per second at a chamber pressure of 64,500 P.S.I..


 For the 140 grain bullet reload if you sighted your 270 WSM hunting rifle in dead on at 240 yards it would only be 2 inches high at 150 yards and only 1.8 inches low at 275 yards which would be an excellent deer, elk and moose load.

270 WSM Load Data:
Test Powder Used = Accurate Magpro.
Test Bullet Used = Hornady / Type = Boat-Tail Spire Point / Diameter = .277".
Test Primer Used = Winchester / WLRM.
Test Case Used = Winchester.
Test Case Trimmed Length = 2.090".
Loaded Cartridge Overall Length = 2.760".
Test Barrel Length = 24".
Test Barrel Twist Rate = 1 in 10".
Hornady
Bullet
Weight
Grains
Hornady
Bullet
Sectional
Density
Hornady
Bullet
Ballistic
Coefficient
Powder
Start
Load
Grains
Start
Load
Velocity
Fps.
Powder
Maximum
Load
Grains
Maximum
Load
Velocity
Fps.
Maximum
Load
Pressure
P.S.I.
140 .261 .486 66.8 2,985 74.2 3,275 64,500
Short Range Ballistics Chart For Above Load:
Recommended
Cartridge
Usage:
Bullet
Weight
Grains
Bullet
Ballistic
Coefficient
Muzzle
Velocity
Fps.
Muzzle
Energy
Ft. Lbs.
Rifle
Zero
100 Yds.
Bullet
Drop
200 Yds.
Bullet
Drop
250 Yds.
Big Game 140 .486 3,275 3,334 0 - 2.2" - 4.8"
Long Range Ballistics Chart For Above Load:
Range: 100 yds. 200 yds. 300 yds. 400 yds. 500 yds. 600 yds. 700 yds.
Velocity Fps. 3,067 2,869 2,679 2,498 2,323 2,156 1,995
Energy Ft.Lbs. 2,924 2,558 2,232 1,939 1,678 1,444 1,237
Trajectory: + 1.1" 0 - 5.3" - 15.5" - 31.3" - 53.5" - 83.2"
Maximum Effective Range For Thin Skinned Big Game: 700 Yards.
Maximum Effective Range For Thick Skinned Big Game: 400 Yards.


.27" Caliber
6.8 Rem.
270 Win.
270 WSM
270 Wby. Mag.

Short Magnums

.17 HM2, .17 HMR, .17 WSM, 5mm Rem. Mag., .22 BB Cap, .22 CB Cap, .22 Short, .22 Long, .22 LR, .22 WRF, .22 WMR.
17 Rem., 204 Ruger, 22 Hornet, 222 Rem., 223 Rem., 22-250 Rem., 220 Swift, 223 WSSM, 243 Win., 6mm Rem., 243 WSSM,
240 Wby. Mag., 250 Sav., 257 Roberts, 25 WSSM, 25-06 Rem., 257 Wby. Mag., 6.5 x 55mm Swedish Mauser, 260 Rem.,
6.5mm Rem. Mag., 264 Win. Mag., 6.8 Rem., 270 Win., 270 WSM, 270 Wby. Mag., 7mm-08 Rem., 280 Rem., 7mm Rem. Mag.,
7mm WSM, 30-30 Win., 308 Win., 30-06 Sprg., 300 Win. Mag., 300 WSM, 300 Wby. Mag., 325 WSM, 338 Win. Mag.,
340 Wby. Mag., 357 Mag., 44 Rem. Mag., 444 Marlin, 45-70 Government.