Current Rifle Cartridges
   .270 Winchester aka .270-06
The 30-06 was introduced in 1906 and soon after wildcatters started experimenting with the cartridge by necking it up
or down to accept other size caliber projectiles.
One of those wildcats was a .270-06, or a .30-06 (.30" or 30 caliber)  necked down to accept .277" or .270 Caliber
(6.8mm) projectiles. Winchester standardized this wildcat and introduced it in 1925 as the .270 Winchester.
Standing the test of time, this is a great hunting cartridge with bullet weights from 90 to 180 grains, velocity from
2,500 to over 3600 feet per second, and energy from 2,590 to over 3,000 foot pound per square inch.
Photos on right of all combos photos are for size comparsion:  (Left) 270 Winchester vs. (Right) 30-06