.270 Weatherby Magnum

.270 Weatherby Magnum
.270 Weatherby 2nd from left
TypeRifle / Hunting
Place of originUSA
Production history
DesignerRoy Weatherby
Designed1943
ManufacturerWeatherby
Specifications
Parent case.300 H&H Magnum
Case typeBelted, bottleneck
Bullet diameter.277 in (7.0 mm)
Neck diameter.303 in (7.7 mm)
Shoulder diameter.492 in (12.5 mm)
Base diameter.512 in (13.0 mm)
Rim diameter.531 in (13.5 mm)
Rim thickness.220 in (5.6 mm)
Case length2.55 in (65 mm)
Overall length3.25 in (83 mm)
Rifling twist1-10"
Primer typeLarge rifle magnum
Ballistic performance
Bullet mass/type Velocity Energy
110 gr (7 g) HP 3,528 ft/s (1,075 m/s) 3,041 ft⋅lbf (4,123 J)
130 gr (8 g) X 3,338 ft/s (1,017 m/s) 3,217 ft⋅lbf (4,362 J)
140 gr (9 g) BT 3,242 ft/s (988 m/s) 3,268 ft⋅lbf (4,431 J)
150 gr (10 g) SBT 3,161 ft/s (963 m/s) 3,329 ft⋅lbf (4,514 J)
Test barrel length: 26"
Source(s): Accurate Powder [1]

The .270 Weatherby Magnum was the first belted magnum based on the .300 H&H Magnum to be developed by Roy Weatherby in 1943.[2] The cartridge is short enough to function in standard-length long actions with a brass length of 2.549" or 64.74mm and an overall length of about 3.295".[2]

  1. ^ ".270 Weatherby data from Accurate Powder" (PDF). Archived from the original (PDF) on 2007-09-28. Retrieved 2007-08-18.
  2. ^ a b Bullets, Speer (2009). Speer Bullets Reloading Manual #14. Speer. p. 340. ISBN 978-0-9791860-0-4.