338-06 A-Square
"A-Square Ammunition Line"
  The History of the .338-06 A-Square:
 The .338-06 A-Square was introduced in 1958 by
changing the (
.333 OKH)* to accept .338"
projectiles and standardized the cartridge as the
.338-06 A-Square; however, this cartridge began as a
wildcat cartridge by necking up the 30-06 case to
accept .338" caliber projectiles before A-Square
standardized the cartridge.
 A-Square went bankrupt and was sold to Sharps Rifle
company some time around 2015.  To my knowledge,
they are not currently loading any of the A-Square line
except the 375 H&H Magnum with an A-Square head
stamp at this writing (03/20/17), but that is not an
A-Square invented the caliber.
* the
.333 OKH was developed by Mr. Charles Oneil,
Mr. Don
Hopkins and Mr.Elmer Keith, well know
wildcat cartridge inventors by necking up a 30-06 case
to accept the British .333"  projectiles.