I'm sure someone's asked this before...

[Stickjockey]

but I can't find it anywhere. Are .30 Gibbs and .30-06 Ackley Improved the same cartridge, and if not, what are the differences?

 

[ReloaderFred]

They're not the same. The .30-06 Ackley Improved was invented in 1944 by P. O. Ackley. The .30 Gibbs was invented in the 1950's by Rocky Gibbs.

The .30-06 Ackley Improved headspaces the same as the original .30-06, but with a sharper shoulder and less taper. The .30 Gibbs pushed the shoulder forward about .196", making the headspace longer, the shoulder sharper and the neck shorter.

The descriptions are on pages 193 and 194 of Barnes Cartridges of the World, 10 Edition.

Hope this helps.

Fred

 

[JackOfAllTradesMasterAtNone]

NO.

I don't have all of the specs at hand, but did research this years ago. The 30-06 and 30-06 Ackley Improved differ only in shoulder angles.

The 30 Gibbs has the shoulder moved out longer and will not chamber in a 30-06. Where-as, an Ackley reamed chamber will accept a standard 30-06 cartridge. A Gibbs reamed chamber would appear to also accept a standard 30-06 cartridge, but I am sure that the shoulder would blow out when fired.


http://www.30gibbs.net

-Steve

 

[steve4102]

The 30-06 and 30-06 Ackley Improved differ only in shoulder angles.

That is correct that the 30-06 and 30-06 AI differ at the shoulder angle, but the AI also has much less taper to the case body.