Home Forums Hunting & Shooting Custom Rifles & Wildcats 280AI- Two reamer types?

Just read this write up below found on Shooting Time Mgazine website. It says you should not use new Nosler 280AI brass or rounds in an older 280AI rifle. Are there now two different chamber reamers for this round?


Be aware...! Headspace differs between the new SAAMI spec .280 Ackley Improved and that of all the .280 Ackleys built in the custom shops over the years. When SAAMI specs were set up, they changed headspacing from the junction point of the cartridge neck and shoulder to that of a point on the shoulder where the shoulder diameter measures .375", the common method used on many SAAMI spec cartridges. Now the SAAMI spec brass is too short for safe use in older, custom .280 Ackley chambers.

Now we have two .280 Ackley chamber reamers, one the original Ackley version, the other is the SAAMI spec version. Customers should be careful not to interchange the two. If factory .280 Ackley brass is used in other .280 Ackley chambers, case separation near the head may occur. Therefore, if you load for any .280 Ackley, you should always start with new standard .280 Remington brass and fireform it into the proper dimension for the chamber you are working with.

There are probably a bunch of different reamer dimensions which vary on the old wildcat .280AI.
You can use the new Nosler SAAMI brass in any of the versions of the .280AI chamber if you follow the bullet jammed into the lands method for the first firing.
People have been pushing shoulders forward on the Gibbs cartridges as well as countless other cartridges for years using this method.

Old news...

Only a couple I tagged, but there are plenty !

http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/5894797/280_A_I_and_Nosler_Brass
https://www.24hourcampfire.com/ubbth...s/5899165/Updated_info_from_Redding_ref_

You can always form a false shoulder on the Nosler brass too.

Here's the SAAMI drawings for the .280AI.

http://www.saami.org/pubresources/cc_drawings/Rifle/280%20Ackley%20Improved.pdf

And here's the SAAMI drawings for the regular .280 Rem.

http://www.saami.org/pubresources/cc_drawings/Rifle/280%20Remington%20-%207mm%20Express.pdf

280 AI Snake Bit!

Start with '06 brass and you've solved a couple of issues: (1) $1/pc nosler custom brass and (2) headspace concerns.

As said above, use .270 necked up, 280 as is or 06 with the false shoulder and worry not. If you get Nosler brass for the headstamp and wan to shoot it in an original spec chamber just drop a few grains and load the bullet to touch the lands so it holds still. If you don't the firing pin will just push it forward in the chamber and it will not go bang.

Another tip I got when fireforming was to lightly oil case bodies only. Worked great for me in my .280 AI

Good advice but I'll happily pay an extra $.50 a case for the Nosler stuff just so I don't have to do any brass prep.
HATE brass prep!

06 brass is shorter than 280 rem brass and 280 brass shrinks enough after fireforming ,think I'll pass on even shorter brass!

The .280 AI, is far from snake bit. Anyone who owns one, including myself knows this. Chances are anyone who owns an AI of any type, is going to be a rifle Loony. Guys like this will do the research, and know the gun and what the chamber is. I have a Cooper .280 AI. I was told by Cooper it was the old AI wilcat spec. I took a fireformed case to work and put it on the optical comparator, it was formed to the new saami spec. If your not sure of your chamber you can always measure your fireformed case. Of all the AI chamberings the .280 AI is the one that makes the most sense to me.

Agreed.