Current Rifle Cartridges
.280 Ackley Improved or .280 Remington  Improved
The first version of this cartridge was invented by P.O. Ackley (a famous wildcatter of over 27 different wildcats) by necking
down the 30-06 Springfield case to 7mm and fire forming them to a 40 degree shoulder angle and calling it the 7mm-06 Wildcat.
After Remington standardized the 280 Remington, Fred Huntington ( another well known wildcatter) tried several should angles
to improve it and the 30 degree angle was the most popular, then Ackley dropped the fire forming of the 30-06 and changed to
the 280 Remington case necked to 7mm with a 40 degree angle for more powder.  Long story short, the Ackley design stood the
test of time and now is a standardized SAAMI cartridge and technically no longer a wildcat.
Please note, picture to
left, the two cartridges
to show you difference
in shoulder neck angle.
Left : 280 Ackley
Improved with a 40
degree angle
Right: 280 Remington
with a 17 degree & 30
minutes angle.